DTC P0720: Countershaft Speed Sensor Circuit Malfunction (3.2CL M/T Model Only)
NOTE:
Record freeze data before trouble shooting DTC P0720.
- 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).
- 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 .
- 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.
- 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.
- 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 .
- 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.
- 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.
- 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.
- 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.
- 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.