DTC Troubleshooting

DTC Troubleshooting: P0731 (64)

DTC P0731:

1st Gear Incorrect Ratio

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review General Troubleshooting Information Reading and Clearing Diagnostic Trouble Codes.

1. Warm up the engine to normal operating temperature (the radiator fan comes on).

2. Make sure that the transmission is filled to the proper level, and check for fluid leaks.

3. Drain the ATF through a strainer. Inspect the strainer for metal debris or excessive clutch material.

Does the strainer have metal debris or excessive clutch material?

YES -

Replace the transmission, then go to step 10.

NO -

Replace the ATF, then go to step 4.

4. Measure the line pressure A/T Pressure Test.

Is the line pressure within the service limits?

YES -

Go to step 5.

NO -

Repair the ATF pump and the regulator valve, or replace the transmission, then go to step 10.

5. Measure the 1st clutch pressure A/T Pressure Test.

Is the 1st clutch pressure within the service limits?

YES -

Go to step 6.

NO -

Shift valve B is stuck. Repair this shift valve and hydraulic circuit, or replace the transmission, then go to step 10.

6. Clear the DTC with the HDS.

7. Test-drive the vehicle in 1st gear in D at speeds above 7 mph (12 km/h) with engine speed 1,000 rpm or higher, for at least 12 seconds. Slow down, and stop the wheels.

8. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0731 indicated?

YES -

Repair the 1st clutch, or replace the transmission, then go to step 10.

NO -

Go to step 9.

9. Monitor the OBD status for P0731 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the HDS indicate PASSED?

YES -

Intermittent failure, the system is OK at this time. If any other DTCs were indicated on step 8, go to the indicated DTC's troubleshooting.�

NO -

Check for poor connections and loose terminals at the input shaft (mainshaft) speed sensor, the output shaft (countershaft) speed sensor, and the PCM, then recheck. If the HDS indicates NOT COMPLETED, return to step 7 and recheck.

10. Test-drive the vehicle in 1st gear in D at speeds above 7 mph (12 km/h) with engine speed 1,000 rpm or higher, for at least 12 seconds. Slow down, and stop the wheels.

11. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0731 indicated?

YES -

Check for poor connections and loose terminals at the input shaft (mainshaft) speed sensor, the output shaft (countershaft) speed sensor, and the PCM, then go to step 1.

NO -

Go to step 12.

12. Monitor the OBD status for P0731 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 11, go to the indicated DTC's troubleshooting.�

NO -

Check for poor connections and loose terminals at the input shaft (mainshaft) speed sensor, the output shaft (countershaft) speed sensor, and the PCM, then go to step 4. If the HDS indicates NOT COMPLETED, return to step 10 and recheck.