Problem in Countershaft Speed Sensor Circuit - M/T Model

DTC P0720: Problem in Countershaft Speed Sensor Circuit - M/T Model

1. Turn the ignition switch OFF.




2. Check for continuity between ECM connector terminal A25 and body ground.

Is there continuity?

YES - Go to step 3.

NO - Repair open in the wire between ECM connector terminal A25 and body ground (G101).

3. Disconnect the mainshaft speed sensor connector.
4. Turn the ignition switch ON (II).




5. Measure voltage between countershaft speed sensor 3P connector terminal No.1 and body ground.

Is there about 5 V?

YES - Go to step 6.

NO - Go to step 16.

6. Turn the ignition switch OFF.




7. Check for continuity between countershaft speed sensor 3P connector terminal No.2 and body ground.

Is there continuity?

YES - Repair short in the wire between ECM connector terminal B16 and the countershaft speed sensor connector.

NO - Go to step 8.




8. Check for Continuity between the countershaft speed sensor 3P connector terminal No.3 and body ground.

Is there continuity?

YES - Go to step 9.

NO - Repair open in the wire between the countershaft speed sensor connector and ground (G101).

9. Turn the ignition switch ON (II).




10. Measure voltage between the countershaft speed sensor 3P connector terminals No.2 and No.3.

Is there about 5 V?

YES - Go to step 11.

NO - Go to step 20.

11. Connect the mainshaft speed sensor 3P connector.




12. Measure voltage between ECM connector terminals B16 and A25.

Is there 0 V to about 5 V?

YES - Go to step 13.

NO - Replace the countershaft speed sensor.

13. Raise the front of the vehicle, make sure it is securely supported, and allow the front wheels to rotate freely.
14. Start the engine,then shift to 1st position and drive the vehicle.




15. Measure voltage between ECM connector terminals B16 and A25.

Is there 1.5 - 3.5 V?

YES - Check for loose terminal fit in the ECM connectors. If necessary, substitute a known-good ECM and recheck.

NO - Replace the countershaft speed sensor.




16. Measure voltage between ECM connector terminals A25 and A30.

Is there 4.75 V - 5.25 V?

YES - Repair open in the wire between ECM connector terminal A30 and the countershaft speed sensor connector.

NO - Go to step 17.

17. Tune the ignition switch OFF.
18. Disconnect ECM connector A (31P).




19. Check for continuity between ECM connector terminal A30 and body ground.

Is there continuity?

YES - Repair short in the wire between ECM connector terminal A30 and the countershaft speed sensor connector.

NO - Check for loose terminal fit in the ECM connectors. If necessary, substitute a known-good ECM and recheck.




20. Measure voltage between ECM connector terminals B16 and A25.

Is there about 5 V?

YES - Repair open in the wire between ECM connector terminal B16 and the countershaft speed sensor connector.

NO - Check for loose terminal fit in the ECM connectors. If necessary, substitute a known-good ECM and recheck.