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 incorrectly, correct the problem, then go to step 37.
3. 4WD model: Raise the vehicle on a lift, make sure it is securely supported, and allow all four wheels to rotate freely.
2WD model: Raise the front of the vehicle, make sure it is securely supported, and allow the front wheels to rotate freely. Or raise the vehicle.
4. Start the engine, and turn the VSA off (the light on the VSA OFF switch comes on). Run the vehicle in D with engine speed at 2,000 rpm or higher for at least 10 seconds, then slow down to a stop.
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 poor connections or loose terminals at the output shaft (countershaft) speed sensor and the PCM. 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 connector C (44P).
9. Check for continuity between PCM connector terminals C40 and body ground, and between C44 and body ground.
Is there continuity?
Yes - Go to step 10.
No - Repair open in the wires between PCM connector terminals C40, C44 and ground (G101), or repair poor ground (G101), then go to step 35.
10. Connect PCM connector C (44P).
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 17.
No - Go to step 14.
14. Turn the ignition switch to LOCK (0).
15. Disconnect PCM connector C (44P).
16. Check for continuity between PCM connector terminal C13 and output shaft (countershaft) speed sensor connector terminal No. 1.
Is there continuity?
Yes - Go to step 19.
No - Repair open in the wire between PCM connector terminal C13 and the output shaft (countershaft) speed sensor, then go to step 35.
17. Turn the ignition switch to LOCK (0).
18. Disconnect PCM connector C (44P).
19. 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 C43 and the output shaft (countershaft) speed sensor connector, then go to step 35.
No - Go to step 20.
20. Check for continuity between PCM connector terminal C14 and output shaft (countershaft) speed sensor connector terminal No. 3.
Is there continuity?
Yes - Go to step 21.
No - Repair open in the wire between the output shaft (countershaft) speed sensor connector and PCM connector terminal C14, then go to step 35.
21. Connect PCM connector C (44P).
22. Turn the ignition switch to ON (II).
23. 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 24.
No - Go to step 28.
24. Connect the output shaft (countershaft) speed sensor connector.
25. Clear the DTC with the HDS.
26. Start the engine, and turn the VSA off (the light on the VSA OFF switch comes on). Run the vehicle in D with engine speed at 2,000 rpm or higher for at least 10 seconds, then slow down to a stop.
27. 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 - Replace the output shaft (countershaft) speed sensor, then go to step 35.
No - Go to step 31.
28. Turn the ignition switch to LOCK (0).
29. Disconnect PCM connector C (44P).
30. Check for continuity between PCM connector terminal C43 and output shaft (countershaft) speed sensor connector terminal No. 2.
Is there continuity?
Yes - Reconnect all connectors, then go to step 31.
No - Repair open in the wire between PCM connector terminal C43 and the output shaft (countershaft) speed sensor, then go to step 35.
31. Update the A/T software in the PCM if it does not have the latest software, or substitute a known-good PCM.
32. Start the engine. Disable the VSA by pressing the VSA OFF switch and run the vehicle in D until it shifts out of 1st gear. Then keep the engine speed above 2,000 rpm for at least 10 seconds. Slow down and stop the wheels.
33. Check for DTC(s) in the DTCs/Freeze Data in 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 34.
34. 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 33, 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 32 and recheck.
35. Reconnect all connectors.
36. Clear the DTC with the HDS.
37. Start the engine. Disable the VSA by pressing the VSA OFF switch and run the vehicle in D until it shifts out of 1st gear. Then keep the engine speed above 2,000 rpm for at least 10 seconds. Slow down and stop the wheels.
38. 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 39.
39. Monitor the OBD STATUS for P0721 or P0722 in the DTCs/Freeze Data in Mode Menu for a pass/fail.
Does the HDS indicate PASSED?
Yes - Troubleshooting is complete. If any other DTCs were indicated on step 38, 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 37 and recheck.