DTC Troubleshooting: P0721 (9-5) (A/T)

DTC Troubleshooting: P0721 (9-5)

DTC P0721:

Problem in Countershaft Speed Sensor Circuit

NOTE:

Record all freeze data and review General Troubleshooting Information before you troubleshoot.
This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

1.	Clear the DTC in CLEAR MENU with the Honda PGM Tester or HDS.

2.	Raise the front of the vehicle, make sure it is securely supported, and allow the front wheels to rotate freely.

3.	Start the engine, drive the vehicle in the [D] position, and hold the vehicle at speeds over 30 mph (48 km/h) for more than 10 seconds. Slow down and stop the wheels.

4.	Check the OBD STATUS in DTCs MENU for a pass/fail test of code P0721. Did the result fail? YES - Go to 5. NO - Intermittent failure, the system is OK at this time. If the tester indicates NOT COMPLETE, return to step 3 and recheck.n

5.	Turn the ignition switch OFF.

6.	Jump the SCS line with the Honda PGM Tester or HDS.

7.	Disconnect the countershaft speed sensor connector, and PCM connector A (31P).

8.	Check for continuity between the No. 2 terminal of the countershaft speed sensor connector and body ground. Is there continuity? YES - Repair short to ground in the wire between PCM connector terminal A18 and the countershaft speed sensor connector.n NO - Go to 9.

9.	Connect PCM connector A (31P).

10.	Turn the ignition switch ON (II).

11.

Measure the voltage between the No. 2 terminal of the countershaft speed sensor connector and body ground.

Is there about 5 V?

YES - Replace the countershaft speed sensor. After replacing the sensor, go to 12, and check that the repair has been completed.

NO - Check for loose or poor connections at PCM connector terminal A18 or an open in the wire between PCM connector terminal A18 and the countershaft speed sensor connector. If the wire 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

12.	Clear the DTC in CLEAR MENU with the Honda PGM Tester or HDS.

13.	Test-drive the vehicle for several minutes under the same conditions as those indicated by the freeze data.

14.	Check the OBD STATUS in DTCs MENU for a pass/fail test of code P0721. Did the result pass? YES - The problem has been corrected.n NO - Return to step 1 and recheck.n