SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET1998SUBURBAN K2500, 7.4 J, PART TIMEREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - TESTS W/CODES - 7.4LDIAGNOSTIC TROUBLE CODESDTC P0338 - CRANKSHAFT POSITION SENSOR CIRCUIT HIGH FREQUENCYDIAGNOSTIC PROCEDURES
1998 Chevrolet Suburban K2500, 7.4 J, Part Time

Diagnostic Procedures

1998 Chevrolet Suburban K2500, 7.4 J, Part TimeSECTION Diagnostic Procedures
  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.
  2. Check if engine starts. If engine starts, go to step 4). If engine does not start, go to next step.
  3. Clear DTCs. Crank engine for 10 seconds. Check if DTC P0338 resets. If DTC P0338 resets, go to next step. If DTC P0338 does not reset, see BASIC TESTING - 7.4L article.
  4. Install scan tool. Start engine and observe engine RPM on scan tool. If RPM fluctuates up to twice the expected RPM, go to step 14). If RPM does not fluctuate up to twice the expected RPM, go to next step.
  5. Disconnect crankshaft position sensor connector. Turn ignition on, with engine off. Using test light, probe signal circuit of crankshaft position sensor connector (engine harness side) to ground. If test light illuminates, go to next step. If test light does not illuminate, go to step 8).
  6. Connect test light between ground circuit and signal circuit of crankshaft position sensor connector (engine harness side). If test light illuminates, go to next step. If test light does not illuminate, go to step 12).
  7. Turn ignition off. Install Gray jumper wires from Connector Test Kit(J 35616-A) between engine harness connector and crankshaft position sensor. Start engine. Using DVOM, check voltage on signal circuit. If voltage reading is 2-3 volts, go to step 16). If voltage is not 2-3 volts, go to step 9).
  8. Turn ignition off. Disconnect VCM harness connector. Using test light connected to battery voltage, probe signal circuit of crankshaft position sensor connector (engine harness side). If test light illuminates, go to step 11). If test light does not illuminate, go to step 15).
  9. Check for open in signal circuit. If circuit is open, go to step 17). If circuit is okay, go to next step.
  10. Check for short to ground in signal circuit. If circuit is shorted, go to step 17). If circuit is okay, go to step 13).
  11. Repair short to ground in ignition feed circuit. After repairs, go to step 19).
  12. Repair open in ground circuit. After repairs, go to step 19).
  13. Check for poor connection at crankshaft position sensor. If a problem is found, go to step 17). If no problem is found, go to next step.
  14. Replace crankshaft position sensor. After replacing sensor, go to step 19).
  15. Check for open in ignition feed circuit. If ignition feed circuit is open, go to step 17). If circuit is okay, go to next step.
  16. Check for poor connection at VCM. If connection is faulty, go to next step. If connection is okay, go to step 18).
  17. Repair circuit as necessary. After repairs, go to step 19).
  18. Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to step 19).
  19. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2).
  20. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTC(s) are displayed, go to applicable DTC test.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

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.