DTC Troubleshooting
DTC P0721: Problem in Output Shaft (Countershaft) Speed Sensor CircuitDTC P0722: Problem in Output Shaft (Countershaft) Speed Sensor Circuit (No Signal Input)
NOTE:
^ 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. Check for proper output shaft (countershaft) speed sensor installation. If the sensor is installed improperly, correct the problem, then go to step 38.
3. Raise the vehicle on a lift, make sure it is securely supported, and allow the all four wheels to rotate freely.
4. Start the engine, and turn the VSA off (the light on the VSA OFF switch comes on). Run the vehicle in either 2nd, 3rd, 4th, or 5th gear (not 1st) in M (sequential sportshift mode) with the engine speed at 2,000 rpm or higher for at least 10 seconds. Slow down and stop the wheels.
5. Monitor the OBD STATUS for P0721 or P0722 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.
Does the HDS indicate FAILED?
YES - Go to step 6.
NO - Intermittent failure, the system is OK at this time. Check for loose or poor connections at the PCM and the output shaft (countershaft) speed sensor connectors. If the HDS indicates NOT COMPLETED, return to step 4 and recheck.
6. Turn the ignition switch to LOCK (0).
7. Jump the SCS line with the HDS.
8. Disconnect PCM connectors A (31P) and B (24P).
9. Check for continuity between PCM connector terminals A3 and body ground, and between B15 and body ground.
Is there continuity?
YES - Go to step 10.
NO - Repair open in the wires between PCM connector terminals A3, B15, and ground (G101, G102), or repair poor ground (G101, G102), then go to step 37.
10. Connect PCM connectors A (31P) and B (24P).
11. Disconnect the output shaft (countershaft) speed sensor connector.
12. Turn the ignition switch to ON (II).
13. Measure the voltage between output shaft (countershaft) speed sensor connector terminal No. 1 and body ground.
Is there about 5 V?
YES - Go to step 14.
NO - Go to step 27.
14. Turn the ignition switch to LOCK (0).
15. Disconnect PCM connector B (24P).
16. Check for continuity between output shaft (countershaft) speed sensor connector terminal No. 2 and body ground.
Is there continuity?
YES - Repair short in the wire between PCM connector terminal B19 and the output shaft (countershaft) speed sensor connector, then go to step 37.
NO - Go to step 17.
17. Disconnect PCM connector C (22P).
18. Check for continuity between PCM connector terminal C4 and output shaft (countershaft) speed sensor connector terminal No. 3.
Is there continuity?
YES - Go to step 19.
NO - Repair open in the wire between the output shaft (countershaft) speed sensor connector and PCM connector terminal C4, then go to step 37.
19. Connect PCM connectors B (24P) and C (22P).
20. Turn the ignition switch to ON (II).
21. Measure the voltage between output shaft (countershaft) speed sensor connector terminals No. 2 and No. 3.
Is there about 5 V?
YES - Go to step 22.
NO - Go to step 26.
22. Connect the output shaft (countershaft) speed sensor connector.
23. Measure the voltage between PCM connector terminals B19 and A3 or B15.
Is there voltage 0 V or about 5 V?
YES - Go to step 24.
NO - Replace the output shaft (countershaft) speed sensor, then go to step 37.
24. Start the engine, and run the vehicle in D (on the lift).
25. While holding the engine at an engine speed 2,000 rpm or higher, measure the voltage between PCM connector terminals B19 and A3 or B15.
Is there 1.5 - 3.5 V?
YES - Go to step 32.
NO - Replace the output shaft (countershaft) speed sensor, then go to step 37.
26. Measure the voltage between PCM connector terminals B19 and A3 or B15.
Is there about 5 V?
YES - Repair open in the wire between PCM connector terminal B19 and the output shaft (countershaft) speed sensor, then go to step 37.
NO - Go to step 32.
27. Measure the voltage between PCM connector terminals C6 and A3 or B15.
Is there about 5 V?
YES - Repair open in the wire between PCM connector terminal C6 and the output shaft (countershaft) speed sensor, then go to step 37.
NO - Go to step 28.
28. Turn the ignition switch to LOCK (0).
29. Jump the SCS line with the HDS.
30. Disconnect PCM connector C (22P).
31. Check for continuity between PCM connector terminal C6 and body ground.
Is there continuity?
YES - Repair short in the wire between PCM connector terminal C6 and the output shaft (countershaft) speed sensor, then go to step 37.
NO - Go to step 32.
32. Reconnect all connectors.
33. Update the A/T software in the PCM if it does not have the latest software, or substitute a known-good PCM.
34. Start the engine. Run the vehicle in either 2nd, 3rd, 4th, or 5th gear (not 1st) in M (sequential sportshift mode) with the engine speed at 2,000 rpm or higher for at least 10 seconds. Slow down and stop the wheels.
35. Check for DTC(s) in the DTCs/Freeze Data in A/T Mode Menu with the HDS.
Is DTC P0721 or P0722 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 36.
36. Monitor the OBD STATUS for P0721 or P0722 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 35, go to the indicated DTC's troubleshooting.
NO - Check for poor connections and loose terminals at the output shaft (countershaft) 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 34 and recheck.
37. Reconnect all connectors.
38. Clear the DTC with the HDS.
39. Start the engine. Run the vehicle in either 2nd, 3rd, 4th, or 5th gear (not 1st) in M (sequential sportshift mode) with the engine speed at 2,000 rpm or higher for at least 10 seconds. Slow down and stop the wheels.
40. Check for DTC(s) in the DTCs/Freeze Data in A/T Mode Menu with the HDS.
Is DTC P0721 or P0722 indicated?
YES - Check for poor connections and loose terminals at the output shaft (countershaft) speed sensor and the PCM, then go to step 1.
NO - Go to step 41.
41. Monitor the OBD STATUS for P0721 or P0722 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 40, go to the indicated DTC's troubleshooting.
NO - Check for poor connections and loose terminals at the output shaft (countershaft) speed sensor and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, return to step 39 and recheck.