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HOMESERVICE MANUALSACURA20043.5RLREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 34 (ENGINE PERFORMANCE SYSTEM SELF-DIAGNOSTICS)DIAGNOSTIC TESTSDTC P0720: COUNTERSHAFT SPEED SENSOR CIRCUIT MALFUNCTION (3.2CL M/T MODEL ONLY)
2004 Acura 3.5RL

DTC P0720: Countershaft Speed Sensor Circuit Malfunction (3.2CL M/T Model Only)

2004 Acura 3.5RLSECTION DTC P0720: Countershaft Speed Sensor Circuit Malfunction (3.2CL M/T Model Only)
WARNING: This page is about a different car, the 2003 Acura 3.2TL and 2003 Acura 3.2CL. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Record freeze data before trouble shooting DTC P0720.
  1. Turn ignition switch off. Check for continuity between ground and PCM 31-pin "A" harness connector terminal No. 25 (Brown/Yellow wire). If there is continuity, go to next step. If there is not continuity, repair open in wire between ground G101 and PCM 31-pin "A" harness connector terminal No. 25 (Brown/Yellow wire).
  2. Turn ignition switch off. Disconnect countershaft speed sensor 3-pin harness connector. See Fig 1 . Turn ignition switch on. Measure voltage between ground and countershaft speed sensor 3-pin harness connector terminal No. 1 (Yellow/Blue wire). If about 5 volts is present, go to next step. If about 5 volts is not present, go to step  8 .
  3. Turn ignition switch off. Disconnect countershaft speed sensor 3-pin harness connector. Check for continuity between ground and countershaft speed sensor 3-pin harness connector terminal No. 2 (Red/Yellow wire). If continuity is present, repair short to ground in Red/Yellow wire between PCM 24-pin "B" harness connector terminal No. 7 and countershaft speed sensor 3-pin harness connector terminal No. 2. If continuity is not present, go to next step.
  4. Check for continuity between ground and countershaft speed sensor 3-pin harness connector terminal No. 3 (Brown/Yellow wire). If continuity is present, go to next step. If continuity is not present, repair open in Brown/Yellow wire between ground G101 and countershaft speed sensor 3-pin harness connector terminal No. 3.
  5. Turn ignition switch on. Measure voltage between countershaft speed sensor 3-pin harness connector terminals No. 2 (Red/Yellow wire) and 3 (Brown/Yellow wire). If about 5 volts is present, go to next step. If about 5 volts is present, go to step  10 .
  6. Connect the countershaft speed sensor 3-pin harness connector. Measure voltage between PCM connector terminals "B" 7 and "A" 25. If 0-5 volts is measured, go to next step. If 0-5 volts is not measured, replace countershaft speed sensor.
  7. Raise vehicle and allow front wheels to rotate freely. Set parking brake and block rear wheels. Start engine and shift into 1st gear. Measure voltage between PCM connector terminals "B" 7 and "A" 25. See Figure . If 1.5-3.5 volts are present, check for loose terminal fit at PCM harness connectors. If necessary, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM. If 1.5-3.5 volts is not present, replace countershaft speed sensor.
  8. Turn ignition switch on. Measure voltage between ground and PCM connector terminals "A" 25 and "A" 30. See Figure . If 4.75-5.25 volts are present, repair open in Yellow/Blue wire between PCM 31-pin "A" harness connector terminal No. 30 and countershaft speed sensor 3-pin harness connector terminal No. 1. If 4.75-5.25 volts is not present, go to next step.
  9. Turn ignition switch off. Disconnect PCM 31-pin "A" harness connector. Check for continuity between ground and PCM 31-pin "A" harness connector terminal No. 30 (Yellow/Blue wire). If continuity is present, repair short to ground in Yellow/Blue wire between PCM 31-pin "A" harness connector terminal No. 30 and countershaft speed sensor 3-pin harness connector terminal No. 1. If continuity is not present, check for loose terminal fit at PCM 31-pin "A" harness connector. If necessary, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  10. Measure voltage between PCM 31-pin "A" harness connector terminals No. 25 (Brown/Yellow wire) and PCM 24-pin "B" harness connector terminal No. 7 (Red/Yellow wire). See Figure . If about 5 volts are present, repair open in wire between PCM 24-pin "B" harness connector terminal No. 7 (Red/Yellow wire) and countershaft speed sensor connector terminal No. 2. If about 5 volts are not present, check for loose terminal fit at PCM connectors. If necessary, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM.
Fig 1: Identifying Mainshaft & Countershaft Speed Sensor 3-Pin Connector (3.2CL M/T)
G00032249Courtesy of AMERICAN HONDA MOTOR CO., INC.
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