Diagnostic Aids

1996 Ford RV Cutaway 5.8 HSECTION Diagnostic Aids

Perform this test when instructed during QUICK TEST  or if directed by other test procedures. This test is used to diagnose the following:

  • Ignition coil packs.
  • Ignition coil wiring harness.
  • Powertrain Control Module (PCM).
  1. Step 1) DTC P0350, P0351 & P0352  Using a spark tester, check for spark at all spark plug wires while cranking engine. If consistent spark is present at all spark plug wires, system is okay and testing is complete. If consistent spark is not present, go to next step.
  2. Step 2) Check Secondary Ignition  Check spark plugs, spark plug wires and coils for damage, looseness or shorting. Repair or replace as necessary. If secondary ignition looks okay, go to next step.
  3. Step 3) Check For COIL PWR At Coil  Turn ignition off. Install EI Diagnostic Harness (007-00059) to Breakout Box (014-000950) and ICM. Use appropriate overlay. Connect right (Blue) coil tee. Connect diagnostic harness negative lead to battery negative terminal. Leave positive lead disconnected. Set diagnostic harness box type switch to "4/6" cylinder position. Turn ignition on. Measure voltage between breakout box test pins J5 (COIL PWR) and J7 (B-). If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open in COIL PWR circuit. Clear PCM memory and repeat QUICK TEST .
    WARNING: Unless otherwise instructed, PCM must not be connected to breakout box when performing ignition system testing.
  4. Step 4) Check C1C Circuit At Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J3 (C1C) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, go to step 12).
  5. Step 5) Check C2C Circuit At Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J6 (C2C) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, go to step 14).
  6. Step 6) Check C1I Circuit At PCM  Turn ignition off. Connect PCM wiring harness connector to breakout box. Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and J26 (C1I). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C1I circuit.
  7. Step 7) Check C2I Circuit At ICM  Leave ignition on. Measure voltage between breakout box test pins J7 (B-) and J52 (C2I). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C2I circuit.
  8. Step 8) Check C1C Circuit At Coil  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Turn ignition on. Measure voltage between breakout box test pins J3 (C1C) and J7 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 16).
  9. Step 9) Check C2C Circuit At Coil  Leave ignition on. Measure voltage between breakout box test pins J6 (C2C) and J7 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 17).
  10. Step 10) Check C1C Circuit At Coil While Cranking  Connect positive lead of EI Diagnostic Harness (007-00059) to battery positive terminal. Connect incandescent test light between breakout box test pins J1 (B+) and J3 (C1C). Crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  11. Step 11) Check C2C Circuit At Coil While Cranking  Connect incandescent test light between breakout box test pins J1 (B+) and J6 (C2C). Crank engine. If test light blinks brightly once every engine revolution, replace coil pack and repeat QUICK TEST . If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  12. Step 12) Check Right Coil  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J3 (C1C) and J7 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace right coil pack. Clear PCM memory and repeat QUICK TEST .
  13. Step 13) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J3 (C1C) and J7(B-). If resistance is less than 10,000 ohms, repair short to ground in C1 circuit. If resistance is 10,000 ohms or more, replace PCM. Repeat QUICK TEST .
  14. Step 14) Check Coil No. 2  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J6 (C2C) and J7 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace coil pack. Clear PCM memory and repeat QUICK TEST .
  15. Step 15) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J6 (C2C) and J7(B-). If resistance is less than 10,000 ohms, repair C2C circuit short to ground. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .
    NOTE: If C2 circuit is shorted to ground, coil damage may occur.
  16. Step 16) Check Coil No. 1  Turn ignition off. Disconnect PCM from vehicle harness connector. Turn ignition on. Measure voltage between breakout box test pins J3 (C1C) and J7 (B-). If DC voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage 0.5 volt or more, repair C1C circuit short to power. Clear PCM memory and repeat QUICK TEST .
  17. Step 17) Check Coil No. 2  Turn ignition on. Measure voltage between breakout box test pins J6 (C2C) and J7 (B-). If DC voltage is less than 0.5 volt, replace PCM. Clear PCM memory and repeat QUICK TEST . If voltage is 0.5 volt or more, repair C2C circuit short to power. Clear PCM memory and repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 17) to step 20). No test procedures have been omitted.
  18. Step 20) DTC P0350, P0351, P0352, P0353 & P0354  Using a spark tester, check for spark at all spark plug wires while cranking engine. If consistent spark is present at all spark plug wires, system is okay and testing is complete. If consistent spark is not present, go to next step.
  19. Step 21) Check For Spark At Right Spark Plugs  If spark is present at right spark plugs, go to next step. If spark is not present at right spark plugs, go to step 38).
  20. Step 22) Check Left Spark Plugs & Wires  Turn ignition off. Check left side spark plugs and wires for damage or wear. Check all wiring harnesses and connectors damage, burned insulation or poor connections. Repair or replace as necessary. If no faults are found, go to next step.
  21. Step 23) Check For COIL PWR At Left Coil  Turn ignition off. Install EI Diagnostic Harness (007-00059) to Breakout Box (014-000950) and ICM. Use appropriate overlay. Connect left (Yellow) coil tee. Connect diagnostic harness negative lead to battery negative terminal. Leave positive lead disconnected. Set diagnostic harness box type switch to 8-cylinder position. Turn ignition on. Measure voltage between breakout box test pins J15 (COIL PWR) and J60 (B-). If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open in COIL PWR circuit. Clear PCM memory and repeat QUICK TEST .
    WARNING: Unless otherwise instructed, PCM must not be connected to breakout box when performing ignition system testing.
  22. Step 24) Check C3I Circuit At Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J30 (LC3C) and J60 (B-). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, go to step 32).
  23. Step 25) Check C4 Circuit At Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J28 (LC4C) and J60 (B-). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, go to step 34).
  24. Step 26) Check C3 Circuit At PCM  Turn ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install a second EEC-V Breakout Box (014-000950). Connect PCM to second breakout box. Turn ignition on. Measure voltage between breakout box test pins J60 (B-) and test pin No. 78 at second breakout box. If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C3 circuit.
  25. Step 27) Check C4 Circuit At PCM  Leave ignition on. Measure voltage between breakout box test pins J60 (B-) and test pin No 104 at second breakout box. If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C4 circuit.
  26. Step 28) Check C3 Circuit At Coil  Turn ignition off. Disconnect left coil from diagnostic harness coil tee. Turn ignition on. Measure voltage between breakout box test pins J30 (C3) and J60 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage 0.5 volt or more, go to step 36).
  27. Step 29) Check C4 Circuit At Coil  Leave ignition on. Measure voltage between breakout box test pins J28 (C4) and J60 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 37).
  28. Step 30) Check C3 Circuit At Coil While Cranking  Connect positive lead of EI Diagnostic Harness (007-00059) to battery positive terminal. Connect incandescent test light between breakout box test pins J57 (B+) and J30 (C3). Crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  29. Step 31) Check C4 Circuit At Coil While Cranking  Connect incandescent test light between breakout box test pins J57 (B+) and J28 (C4). Crank engine. If test light blinks brightly once every engine revolution, replace left coil pack and repeat QUICK TEST . If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  30. Step 32) Check Left Coil Pack  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J30 (C3) and J60 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace left coil pack. Clear PCM memory and repeat QUICK TEST .
  31. Step 33) Check C3 Circuit  Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J30 (C3) and J60 (B-). If resistance is less than 10,000 ohms, repair short to ground in C3 circuit. If resistance is 10,000 ohms or more, replace PCM. Repeat QUICK TEST .
  32. Step 34) Check C4 Circuit  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J28 (C4) and J60 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace left coil pack. Clear PCM memory and repeat QUICK TEST .
  33. Step 35) Leave ignition off. Disconnect PCM wiring harness  connector. Measure resistance between breakout box test pins J28 (C4) and J60 (B-). If resistance is less than 10,000 ohms, repair C4 circuit short to ground. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .
    NOTE: If C4 circuit is shorted to ground, coil damage may occur.
  34. Step 36) Turn ignition on. Measure voltage between breakout box test pins J28 (C4) and J60 (B-). If voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage is 0.5 volts or more, repair C4 circuit short to power and repeat QUICK TEST .
  35. Step 37) Check C3 Circuit  Turn ignition off. Disconnect PCM from vehicle harness connector. Turn ignition on. Measure voltage between breakout box test pins J30 (C3) and J60 (B-). If DC voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage is 0.5 volt or more, repair C3 circuit short to power. Clear PCM memory, repeat QUICK TEST .
  36. Step 38) Check Right Spark Plugs & Wires  Turn ignition off. Check right side spark plugs and wires for damage or wear. Check all wiring harnesses and connectors damage, burned insulation or poor connections. Repair or replace as necessary and repeat QUICK TEST . If no faults are found, go to next step.
  37. Step 39) Check For COIL PWR At Right Coil  Turn ignition off. Connect EI Diagnostic Harness (007-00059) to Breakout Box (014-000950). Use appropriate overlay. Connect right coil tee. Connect diagnostic harness negative lead to battery negative terminal. Leave positive lead disconnected. Set diagnostic harness box type switch to 8-cylinder position. Turn ignition on. Measure voltage between breakout box test pins J26 (COIL PWR) and J60 (B-). If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open in COIL PWR circuit. Clear PCM memory and repeat QUICK TEST .
    WARNING: Unless otherwise instructed, PCM must not be connected to breakout box when performing ignition system testing.
  38. Step 40) Check C1 Circuit At Right Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J23 (RC1C) and J60 (B-). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, go to step 48).
  39. Step 41) Check C2 Circuit At Right Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J24 (RC2C) and J60 (B-). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, go to step 50).
  40. Step 42) Check C1 Circuit At PCM  Turn ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install a second EEC-V Breakout Box (014-000950). Connect PCM to second breakout box. Turn ignition on. Measure voltage between breakout box test pins J60 (B-) and test pin No. 26 at second breakout box. If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C1 circuit.
  41. Step 43) Check C2 Circuit At PCM  Leave ignition on. Measure voltage between breakout box test pins J60 (B-) and test pin No. 52 (C2) at second breakout box. If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C2 circuit.
  42. Step 44) Check C1 Circuit At Coil  Turn ignition off. Disconnect right coil from diagnostic harness coil tee. Turn ignition on. Measure voltage between breakout box test pins J23 (C1) and J60 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage 0.5 volt or more, go to step 52).
  43. Step 45) Check C2 Circuit At Coil  Leave ignition on. Measure voltage between breakout box test pins J24 (C2) and J60 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 53).
  44. Step 46) Check C1 Circuit At Coil While Cranking  Connect positive lead of EI Diagnostic Harness (007-00059) to battery positive terminal. Connect incandescent test light between breakout box test pins J57 (B+) and J23 (C1). Crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  45. Step 47) Check C2 Circuit At Coil While Cranking  Connect incandescent test light between breakout box test pins J57 (B+) and J24 (C2). Crank engine. If test light blinks brightly once every engine revolution, replace right coil pack and repeat QUICK TEST . If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  46. Step 48) Check C1 Circuit  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J23 (C1) and J60 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace right coil pack. Clear PCM memory and repeat QUICK TEST .
  47. Step 49) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J23 (C1) and J60 (B-). If resistance is less than 10,000 ohms, repair short to ground in C1 circuit. If resistance is 10,000 ohms or more, replace PCM. Repeat QUICK TEST .
  48. Step 50) Check C2 Circuit  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J24 (C2) and J60 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace right coil pack. Clear PCM memory and repeat QUICK TEST .
  49. Step 51) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J24 (C2) and J60 (B-). If resistance is less than 10,000 ohms, repair C2 circuit short to ground. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .
    NOTE: If C2 circuit is shorted to ground, coil damage may occur.
  50. Step 52) Check C1 Circuit  Turn ignition on. Measure voltage between breakout box test pins J23 (C1) and J60 (B-). If voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage is 0.5 volts or more, repair C1 circuit short to power and repeat QUICK TEST .
  51. Step 53) Check C2 Circuit  Turn ignition off. Disconnect PCM from vehicle harness connector. Turn ignition on. Measure voltage between breakout box test pins J24 (C2) and J60 (B-). If DC voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage is 0.5 volt or more, repair C2 circuit short to power. Clear PCM memory, repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 53) to step 60). No test procedures have been omitted.
  52. Step 60) DTC P0350, P0351, P0352 & P0353  Using a spark tester, check for spark at all spark plug wires while cranking engine. If consistent spark is present at all spark plug wires, system is okay and testing is complete. If consistent spark is not present, go to next step.
  53. Step 61) Check Secondary Ignition  Check spark plugs, spark plug wires and coils for damage, looseness or shorting. Repair or replace as necessary. If secondary ignition looks okay, go to next step.
  54. Step 62) Check For COIL PWR At Coil  Turn ignition off. Install EI Diagnostic Harness (007-00059) to Breakout Box (014-000950) and ICM. Use appropriate overlay. Connect (Blue) coil tee. Connect diagnostic harness negative lead to battery negative terminal. Leave positive lead disconnected. Set diagnostic harness box type switch to 4/6-cylinder position. Turn ignition on. Measure voltage between breakout box test pins J5 (COIL PWR) and J7 (B-). If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open in COIL PWR circuit. Clear PCM memory and repeat QUICK TEST .
    WARNING: Unless otherwise instructed, PCM must not be connected to breakout box when performing ignition system testing.
  55. Step 63) Check C1 Circuit At Coil Pack  Turn ignition on. Measure voltage as follows:
    • For horizontal connector coil pack, between breakout box test pins J3 (C1C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J6 (C1C) and J7 (B-).

    If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, go to step 75).

  56. Step 64) Check C2 Circuit At Coil Pack  Turn ignition on. Measure voltage as follows:
    • For horizontal connector coil pack, between breakout box test pins J6 (C2C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J3 (C2C) and J7 (B-).

    If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, go to step 77).

  57. Step 65) Check C3 Circuit At Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J10 (C3C) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, go to step 79).
  58. Step 66) Check C1 Circuit At PCM  Turn ignition off. Connect PCM wiring harness connector to breakout box. Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and J26 (C1I). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C1 circuit.
  59. Step 67) Check C2 Circuit At PCM  Leave ignition on. Measure voltage between breakout box test pins J7 (B-) and J52 (C2I). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C2 circuit.
  60. Step 68) Check C3 Circuit At PCM  Leave ignition on. Measure voltage between breakout box test pins J7 (B-) and J78 (C3). If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C3 circuit.
  61. Step 69) Check C1 Circuit At Coil  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Turn ignition on. Measure voltage as follows:
    • For horizontal connector coil pack, between breakout box test pins J3 (C1C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J6 (C1C) and J7 (B-).

    If DC voltage is less than 0.5 volts, go to next step. If voltage is 0.5 volts or more, go to step 81).

  62. Step 70) Check C2 Circuit At Coil  Leave ignition on. Measure voltage as follows:
    • For horizontal connector coil pack, between breakout box test pins J6 (C2C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J3 (C2C) and J7 (B-).

    If DC voltage is less than 0.5 volts, go to next step. If voltage is 0.5 volts or more, go to step 82).

  63. Step 71) Check C3 Circuit At Coil  Leave ignition on. Measure voltage between breakout box test pins J10 (C3C) and J7 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 83).
  64. Step 72) Check C1 Circuit At Coil While Cranking  Connect positive lead of EI Diagnostic Harness (007-00059) to battery positive terminal. Connect incandescent test light as follows:
    • For horizontal connector coil pack, between breakout box test pins J1 (B+) and J3 (C1C).
    • For vertical connector coil pack, between breakout box test pins J1 (B+) and J6 (C1C).

    Crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .

  65. Step 73) Check C2 Circuit At Coil While Cranking  Connect incandescent test light as follows:
    • For horizontal connector coil pack, between breakout box test pins J1 (B+) and J6 (C2C).
    • For vertical connector coil pack, between breakout box test pins J1 (B+) and J3 (C2C).

    Crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .

  66. Step 74) Check C3 Circuit At Coil While Cranking  Connect incandescent test light between breakout box test pins J1 (B+) and J10 (C3C). Crank engine. If test light blinks brightly once every engine revolution, replace coil pack and repeat QUICK TEST . If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  67. Step 75) Check C1 Circuit For Short To Ground  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins as follows:
    • For horizontal connector coil pack, between breakout box test pins J3 (C1C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J6 (C1C) and J7 (B-).

    If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace coil pack. Clear PCM memory and repeat QUICK TEST .

  68. Step 76) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins as follows:
    • For horizontal connector coil pack, between breakout box test pins J3 (C1C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J6 (C1C) and J7 (B-).

    If resistance is less than 10,000 ohms, repair short to ground in C1 circuit. If resistance is 10,000 ohms or more, replace PCM. Repeat QUICK TEST .

  69. Step 77) Check Coil No. 2  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance as follows:
    • For horizontal connector coil pack, between breakout box test pins J6 (C2C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J3 (C2C) and J7 (B-).

    If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace coil pack. Clear PCM memory and repeat QUICK TEST .

  70. Step 78) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance as follows:
    • For horizontal connector coil pack, between breakout box test pins J6 (C2C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J3 (C2C) and J7 (B-).

    If resistance is less than 10,000 ohms, repair C2 circuit short to ground. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .

  71. Step 79) Check C3 Circuit  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J7 (B-) and J10 (C3C). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace coil pack. Clear PCM memory and repeat QUICK TEST .
  72. Step 80) Turn ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J7 (B-) and J10 (C3C). If resistance is less than 10,000 ohms, repair C3 circuit short to ground. If resistance is 10,000 ohms or more, replace PCM. Clear PCM memory and repeat QUICK TEST .
  73. Step 81) Check C1 Circuit  Turn ignition off. Disconnect PCM wiring harness connector. Turn ignition on. Measure voltage as follows:
    • For horizontal connector coil pack, between breakout box test pins J3 (C1C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J6 (C1C) and J7 (B-).

    If voltage is 0.5 volts or more, repair C1 circuit short to power. If DC voltage is less than 0.5 volts, replace PCM. Clear PCM memory and repeat QUICK TEST .

  74. Step 82) Check C1 Circuit  Turn ignition off. Disconnect PCM wiring harness connector. Turn ignition on. Measure voltage as follows:
    • For horizontal connector coil pack, between breakout box test pins J6 (C2C) and J7 (B-).
    • For vertical connector coil pack, between breakout box test pins J3 (C2C) and J7 (B-).

    If voltage is 0.5 volts or more, repair C2 circuit short to power. If DC voltage is less than 0.5 volts, replace PCM. Clear PCM memory and repeat QUICK TEST .

  75. Step 83) Turn ignition off. Disconnect PCM wiring harness connector. Measure voltage between breakout box test pins J7 (B-) and J10 (C3C). If voltage is 0.5 volts or more, repair C3 circuit short to power. If DC voltage is less than 0.5 volts, replace PCM. Clear PCM memory and repeat QUICK TEST .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 83) to step 90). No test procedures have been omitted.
  76. Step 90) DTC P0350, P0351, P0352, P0353 & P0354  Using a spark tester, check for spark at all spark plug wires while cranking engine. If consistent spark is present at all spark plug wires, ignition system is okay and testing is complete. If consistent spark is not present, go to next step.
  77. Step 91) Check For Spark At Right Spark Plugs  If spark is present at right spark plugs, go to next step. If spark is not present at right spark plugs, go to step 108).
  78. Step 92) Check Left Spark Plugs & Wires  Turn ignition off. Check left side spark plugs and wires for damage or wear. Check all wiring harnesses and connectors damage, burned insulation or poor connections. Check sensor shield connector. Repair or replace as necessary. If no faults are found, go to next step.
  79. Step 93) Check For COIL PWR At Left Coil  Turn ignition off. Install EI Diagnostic Harness (007-00059) to Breakout Box (014-000950) and ICM. Use appropriate overlay. Connect left (Yellow) coil tee. Connect diagnostic harness negative lead to battery negative terminal. Leave positive lead disconnected. Set diagnostic harness box type switch to 8-cylinder position. Turn ignition on. Measure voltage between breakout box test pins J11 (COIL PWR) and J7 (B-). If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open in COIL PWR circuit. Clear PCM memory and repeat QUICK TEST .
    WARNING: Unless otherwise instructed, PCM must not be connected to breakout box when performing ignition system testing.
  80. Step 94) Check C3I Circuit At Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J10 (LC3C) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, go to step 102).
  81. Step 95) Check C4 Circuit At Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J18 (LC4C) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, go to step 104).
  82. Step 96) Check C3 Circuit At PCM  Turn ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install a second EEC-V Breakout Box (014-000950). Connect PCM to second breakout box. Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and test pin No. 78 at second breakout box. If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C3 circuit.
  83. Step 97) Check C4 Circuit At PCM  Leave ignition on. Measure voltage between breakout box test pins J7 (B-) and test pin No 104 at second breakout box. If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, repair open in C4 circuit.
  84. Step 98) Check C3 Circuit At Coil  Turn ignition off. Disconnect left coil from diagnostic harness coil tee. Turn ignition on. Measure voltage between breakout box test pins J10 (LC3) and J7 (B-). If DC voltage less than 0.5 volt, go to next step. If DC voltage 0.5 volt or more, go to step 106).
  85. Step 99) Check C4 Circuit At Coil  Leave ignition on. Measure voltage between breakout box test pins J18 (C4) and J7 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 107).
  86. Step 100) Check C3 Circuit At Coil While Cranking  Connect positive lead of EI Diagnostic Harness (007-00059) to battery positive terminal. Connect incandescent test light between breakout box test pins J1 (B+) and J10 (LC3). Crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  87. Step 101) Check C4 Circuit At Coil While Cranking  Connect incandescent test light between breakout box test pins J1 (B+) and J18 (LC4). Crank engine. If test light blinks brightly once every engine revolution, replace left coil pack and repeat QUICK TEST . If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  88. Step 102) Check Left Coil Pack  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J10 (C3C) and J7 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace left coil pack. Clear PCM memory and repeat QUICK TEST .
  89. Step 103) Check C3 Circuit  Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J10 (C3C) and J7 (B-). If resistance is less than 10,000 ohms, repair short to ground in C3 circuit. If resistance is 10,000 ohms or more, replace PCM. Repeat QUICK TEST .
  90. Step 104) Check C4 Circuit  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J18 (LC4) and J7 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace left coil pack. Clear PCM memory and repeat QUICK TEST .
  91. Step 105) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J18 (LC4) and J7 (B-). If resistance is less than 10,000 ohms, repair C4 circuit short to ground. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .
    NOTE: If C4 circuit is shorted to ground, coil damage may occur.
  92. Step 106) Check C3 Circuit  Turn ignition off. Disconnect PCM from vehicle harness connector. Turn ignition on. Measure voltage between breakout box test pins J10 (LC3) and J7 (B-). If DC voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If DC voltage is 0.5 volt or more, repair C3 circuit short to power. Clear PCM memory, repeat QUICK TEST .
  93. Step 107) Check C4 Circuit  Turn ignition off. Disconnect PCM wiring harness connector. Turn ignition on. Measure voltage between breakout box test pins J18 (LC4) and J7 (B-). If voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage is 0.5 volts or more, repair C4 circuit short to power and repeat QUICK TEST .
  94. Step 108) Check Right Spark Plugs & Wires  Turn ignition off. Check right side spark plugs and wires for damage or wear. Check all wiring harnesses and connectors damage, burned insulation or poor connections. Repair or replace as necessary and repeat QUICK TEST . If no faults are found, go to next step.
  95. Step 109) Check For COIL PWR At Right Coil  Turn ignition off. Connect right coil tee. Turn ignition on. Measure voltage between breakout box test pins J5 (COIL PWR) and J7 (B-). If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open in COIL PWR circuit to right coil. Clear PCM memory and repeat QUICK TEST .
    WARNING: Unless otherwise instructed, PCM must not be connected to breakout box when performing ignition system testing.
  96. Step 110) Check C1 Circuit At Right Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J3 (RC1C) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, go to step 118).
  97. Step 111) Check C2 Circuit At Right Coil Pack  Turn ignition on. Measure voltage between breakout box test pins J6 (RC2) and J7 (B-). If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, go to step 120).
  98. Step 112) Check C1 Circuit At PCM  Turn ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install a second EEC-V Breakout Box (014-000950). Connect PCM to second breakout box. Turn ignition on. Measure voltage between breakout box test pins J7 (B-) and test pin No. 26 at second breakout box. If DC voltage is more than 10.0 volts, go to next step. If DC voltage is 10.0 volts or less, repair open in C1 circuit.
  99. Step 113) Check C2 Circuit At PCM  Leave ignition on. Measure voltage between breakout box test pins J7 (B-) and test pin No. 52 (RC2) at second breakout box. If DC voltage is more than 10.0 volts, go to next step. If voltage is 10.0 volts or less, repair open in C2 circuit.
  100. Step 114) Check C1 Circuit At Coil  Turn ignition off. Disconnect right coil from diagnostic harness coil tee. Turn ignition on. Measure voltage between breakout box test pins J3 (RC1) and J7 (B-). If DC voltage less than 0.5 volt, go to next step. If DC voltage 0.5 volt or more, go to step 122).
  101. Step 115) Check C2 Circuit At Coil  Leave ignition on. Measure voltage between breakout box test pins J24 (C2) and J60 (B-). If DC voltage is less than 0.5 volt, go to next step. If DC voltage is 0.5 volt or more, go to step 53).
  102. Step 116) Check C1 Circuit At Coil While Cranking  Turn ignition off. Reconnect coil lead. Connect positive lead of EI Diagnostic Harness (007-00059) to battery positive terminal. Connect incandescent test light between breakout box test pins J1 (B+) and J3 (RC1). Using starter, crank engine. If test light blinks brightly once every engine revolution, go to next step. If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  103. Step 117) Check C2 Circuit At Coil While Cranking  Connect incandescent test light between breakout box test pins J1 (B+) and J6 (RC2). Using starter, crank engine. If test light blinks brightly once every engine revolution, replace right coil pack and repeat QUICK TEST . If test light does not blink as indicated, replace PCM and repeat QUICK TEST .
  104. Step 118) Check C1 Circuit  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J3 (RC1) and J7 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace right coil pack. Clear PCM memory and repeat QUICK TEST .
  105. Step 119) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J3 (RC1) and J7 (B-). If resistance is less than 10,000 ohms, repair short to ground in C1 circuit. If resistance is 10,000 ohms or more, replace PCM. Repeat QUICK TEST .
    NOTE: If C1 circuit is shorted to ground, coil damage may occur.
  106. Step 120) Check C2 Circuit  Turn ignition off. Disconnect coil from diagnostic harness coil tee. Measure resistance between breakout box test pins J6 (RC2) and J7 (B-). If resistance is less than 2000 ohms, go to next step. If resistance is 2000 ohms or more, replace right coil pack. Clear PCM memory and repeat QUICK TEST .
  107. Step 121) Leave ignition off. Disconnect PCM wiring harness connector. Measure resistance between breakout box test pins J24 (C2) and J60 (B-). If resistance is less than 10,000 ohms, repair C2 circuit short to ground. If resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST .
    NOTE: If C2 circuit is shorted to ground, coil damage may occur.
  108. Step 122) Check C1 Circuit  Turn ignition off. Disconnect PCM wiring harness connector.Turn ignition on. Measure voltage between breakout box test pins J3 (RC1) and J7 (B-). If voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage is 0.5 volts or more, repair C1 circuit short to power and repeat QUICK TEST .
  109. Step 123) Check C2 Circuit  Turn ignition off. Disconnect PCM from vehicle harness connector. Turn ignition on. Measure voltage between breakout box test pins J6 (RC2) and J7 (B-). If DC voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST . If voltage is 0.5 volt or more, repair C2 circuit short to power. Clear PCM memory, repeat QUICK TEST .
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.