DTC Troubleshooting
DTC P0718: Input Shaft (Mainshaft) Speed Sensor Intermittent FailureNOTE:
^ Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information.
^ This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.
1. Clear the DTC with the HDS.
2. Test-drive the vehicle with the shift lever in D, and let the transmission shift through all five gears at speeds over 12 mph (20 km/h). Slow down, and stop the wheels.
3. Monitor the OBD status for P0718 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.
Does the HDS indicate FAILED?
YES - Go to step 4.
NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the input shaft (mainshaft) speed sensor and the PCM. If the HDS indicates NOT COMPLETED, return to step 2 and recheck.
4. Turn the ignition switch to LOCK (0).
5. Disconnect the input shaft (mainshaft) speed sensor connector, and inspect the connector and connector terminals to be sure they are making good contact.
Are the connector terminals OK?
YES - Go to step 6.
NO - Repair the connector terminals, then go to step 6.
6. Connect the input shaft (mainshaft) speed sensor connector.
7. Test-drive the vehicle with the shift lever in D, and let the transmission shift through all five gears at speeds over 12 mph (20 km/h). Slow down, and stop the wheels.
8. Monitor the OBD status for P0718 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.
Does the HDS indicate FAILED?
YES - Go to step 9.
NO - Troubleshooting is complete. If the HDS indicates NOT COMPLETED, return to step 7 and recheck.
9. Turn the ignition switch to LOCK (0).
10. Jump the SCS line with the HDS.
11. Disconnect PCM connectors B (49P) and C (49P).
12. Check for continuity between PCM connector terminals B41 and body ground, and between C41 and body ground.
Is there continuity?
YES - Go to step 13.
NO - Repair open in the wires between (PCM), connector terminals B41, C41 and ground (G101), or repair poor ground (G101), then go to step 34.
13. Connect PCM connectors B (49P) and C (49P).
14. Disconnect the input shaft (mainshaft) speed sensor connector.
15. Turn the ignition switch to ON (II).
16. Measure the voltage between input shaft (mainshaft) speed sensor connector terminal No. 1 and body ground.
Is thereabout 5 V?
YES - Go to step 17.
NO - Go to step 26.
17. Turn the ignition switch to LOCK (0).
18. Disconnect PCM connector B (49P).
19. Check for continuity between input shaft (mainshaft) speed sensor connector terminal No. 2 and body ground.
Is there continuity?
YES - Repair short in the wire between PCM connector terminal B37 and the input shaft (mainshaft) speed sensor connector, then go to step 34.
NO - Go to step 20.
20. Connect PCM connector B (49P).
21. Turn the ignition switch to ON (II).
22. Measure the voltage between input shaft (mainshaft) speed sensor connector terminal No. 2 and body ground.
Is there about 5 V?
YES - Replace the input shaft (mainshaft) speed sensor, then go to step 34.
NO - Go to step 23.
23. Turn the ignition switch to LOCK (0).
24. Disconnect PCM connector B (49P).
25. Check for continuity between PCM connector terminal B37 and input shaft (mainshaft) speed sensor connector terminal No. 2.
YES - Go to step 29.
NO - Repair open in the wire between PCM connector terminal B37 and the input shaft (mainshaft) speed sensor, then go to step 34.
26. Turn the ignition switch to LOCK (0).
27. Disconnect PCM connector C (49P).
28. Check for continuity between PCM connector terminal C12 and input shaft (mainshaft) speed sensor connector terminal No. 1.
Is there continuity?
YES - Go to step 29.
NO - Repair open in the wire between PCM connector terminal C12 and the input shaft (mainshaft) speed sensor, then go to step 34.
29. Reconnect all connectors.
30. Update the A/T software in the PCM if it does not have the latest software, or substitute a known-good PCM.
31. Test-drive the vehicle with the shift lever in D, and let the transmission shift through all five gears at speeds over 12 mph (20 km/h). Slow down, and stop the wheels.
32. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0718 indicated?
YES - If the (PCM), was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1.
NO - Go to step 33.
33. Monitor the OBD status for P0718 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.
Does the HDS indicate PASSED?
YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other DTCs were indicated on step 32, go to the indicated DTC's troubleshooting.
NO - Check for poor connections and loose terminals at the input shaft (mainshaft) speed sensor and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, return to step 31 and recheck.
34. Reconnect all connectors.
35. Clear the DTC with the HDS.
36. Test-drive the vehicle with the shift lever in D, and let the transmission shift through all five gears at speeds over 12 mph (20 km/h). Slow down, and stop the wheels.
37. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0718 indicated?
YES - Check for poor connections and loose terminals at the input shaft (mainshaft) speed sensor and the PCM, then go to step 1.
NO - Go to step 38.
38. Monitor the OBD status for P0718 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.
Does the HDS indicate PASSED?
YES - Troubleshooting is complete. If any other DTCs were indicated on step 37, go to the indicated DTC's troubleshooting.
NO - Check for poor connections and loose terminals at the input shaft (mainshaft) speed sensor and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, return to step 36 and recheck.