DTC Troubleshooting: P0721 (9-5)

DTC P0721:  Problem in Output Shaft (Countershaft) Speed Sensor Circuit

NOTE:

1.Clear the DTC with the HDS.

2.Check for proper output shaft (countershaft) speed sensor installation.

3.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, run the vehicle in the D position with engine speed 2,000 rpm (min-1) or higher for more than 10 seconds. Slow down and stop the wheels.

5.Monitor the OBD status for P0721 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the result indicate FAILED?


YES - Go to 6.


NO - Intermittent failure, the system is OK at this time. Check for loose or poor connections at the PCM and output shaft (countershaft) speed sensor connectors. If the tester indicates NOT COMPLETED, return to 4 and recheck.n

6.Turn the ignition switch OFF.

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 10.


NO - Repair open in the wires between PCM connector terminals C40, C44, and ground (G101), or repair poor ground (G101), then go to 32.

10.Connect PCM connector C (44P).

11.Disconnect the output shaft (countershaft) speed sensor connector.

12.Turn the ignition switch ON (II).

13.Measure voltage between output shaft (countershaft) speed sensor connector terminal No. 1 and body ground.

 

Is there about 5 V?


YES - Go to 18.


NO - Go to 14.

14.Turn the ignition switch OFF.

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 17.


NO - Repair open in the wire between PCM connector terminal C13 and the output shaft (countershaft) speed sensor, then go to 32.

17.Check for continuity between PCM connector terminal C13 and body ground.

 

Is there continuity?


YES - Repair short to ground in the wire between PCM connector terminal C13 and the output shaft (countershaft) speed sensor, then go to 32.


NO - Check for loose or poor connections at PCM connector terminal C13. If the connection is OK, update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original  PCM.n

18.Turn the ignition switch OFF.

19.Disconnect PCM connector C (44P).

20.Check for continuity between output shaft (countershaft) speed sensor connector terminal No. 2 and body ground.

 

Is there continuity?


YES - Repair short to ground in the wire between PCM connector terminal C43 and output shaft (countershaft) speed sensor connector, then go to 32.


NO - Go to 21.

21.Check for continuity between PCM connector terminal C14 and output shaft (countershaft) speed sensor connector terminal No. 3.

 

Is there continuity?


YES - Go to 22.


NO - Repair open in the wire between output shaft (countershaft) speed sensor connector and PCM connector terminal C14, then go to 32.

22.Connect PCM connector C (44P).

23.Turn the ignition switch ON (II).

24.Measure voltage between output shaft (countershaft) speed sensor connector terminals No. 2 and No. 3.

 

Is there about 5 V?


YES - Go to 28.


NO - Go to 25.

25.Turn the ignition switch OFF.

26.Disconnect PCM connector C (44P).

27.Check for continuity between PCM connector terminal C43 and output shaft (countershaft) speed sensor connector terminal No. 2.

 

Is there continuity?


YES - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original  PCM.n


NO - Repair open in the wire between PCM connector terminal C43 and the output shaft (countershaft) speed sensor, then go to 32.

28.Connect the output shaft (countershaft) speed sensor connector.

29.Clear the DTC with the HDS.

30.Start the engine, run the vehicle in the D position with engine speed 2,000 rpm (min-1) or higher for more than 10 seconds. Slow down and stop the wheels.

31.Monitor the OBD status for P0721 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the result indicate FAILED?


YES - Replace the output shaft (countershaft) speed sensor, then go to 32.


NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original  PCM.n


32.Clear the DTC with the HDS.

33.Start the engine, run the vehicle in the D position with engine speed 2,000 rpm (min-1) or higher for more than 10 seconds. Slow down and stop the wheels.

34.Monitor the OBD status for P0721 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the result indicate PASSED?


YES - Troubleshooting is complete.n


NO - Return to 6 and recheck.