DTC P0720/9: Countershaft Speed Sensor
WARNING: This page is about a different variant/trim than selected.
NOTE:
For circuit and terminal identification, see CONNECTOR IDENTIFICATION and WIRING DIAGRAMS
.
- Using scan tool, retrieve freeze data. Clear DTCs and road test vehicle under same conditions freeze data was recorded. If DTC resets, go to next step. If DTC does not reset, problem is intermittent, check countershaft speed sensor and PCM connections.
- Ensure countershaft speed sensor is installed properly. See COUNTERSHAFT & MAINSHAFT SPEED SENSOR under REMOVAL & INSTALLATION. If countershaft speed sensor is properly installed, go to next step. If countershaft speed sensor is not properly installed, reinstall and road test.
- Disconnect countershaft speed sensor harness connector. Measure resistance between sensor terminals. If resistance is 400-600 ohms, go to next step. If resistance is not 400-600 ohms, replace countershaft speed sensor. See COUNTERSHAFT & MAINSHAFT SPEED SENSOR under REMOVAL & INSTALLATION.
- Disconnect PCM harness connector "D". Check for continuity between PCM harness connector "D" terminal No. 10 (Blue wire) and ground, and between terminal No. 16 (Green wire) and ground. If continuity is present, repair short to ground in Green and/or Blue wire between PCM and countershaft speed sensor. If continuity is not present, go to next step.
- Reconnect countershaft speed sensor harness connector. Measure resistance between PCM harness connector "D" terminals No. 10 (Blue wire) and 16 (Green wire). If resistance is 400-600 ohms, check for loose PCM harness connectors. If necessary, substitute a known-good PCM and retest. If resistance is not 400-600 ohms, repair loose connection or open in Green and/or Blue wire between PCM harness connector and countershaft speed sensor harness connector.