DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P0731

DTC P0731 : 1st Gear Incorrect Ratio

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review the General Troubleshooting Information How To Troubleshoot The A/T System.

1. ATF check:

ATF check
-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 do the repair verification.
-NO- Replace the ATF , then go to step 2.

2. Stall speed rpm check:

Stall speed rpm check
-1. Check stall speed with the shift lever in 1 A/T Stall Speed Test.

Is the stall speed within the service limits?
-YES- Stall speed rpm is OK. Go to step 3.
-NO- Faulty shift valves A and D. Repair the hydraulic circuit related with shift valves A and D, or replace the main valve body (shift valves A and D) or the transmission , then do the repair verification.

3. Line pressure check:

Line pressure check
-1. Measure the line pressure A/T Pressure Test.

Is the line pressure within the service limit?
-YES- Line pressure is OK. Go to step 4.
-NO- Faulty ATF pump and regulator valve. Replace the main valve body (ATF pump), the regulator valve body (regulator valve) , or the transmission , then do the repair verification.

4. 1st clutch pressure check:

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

Is the 1st clutch pressure within the service limit?
-YES- 1st clutch pressure is OK. Go to step 5.
-NO- Faulty shift valves B and C. Repair the hydraulic circuit related with shift valves B and C, or replace the servo body (shift valve B), the main valve body (shift valve C) , or the transmission , then do the repair verification.

5. Problem verification:

Problem verification
-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with HDS.

-3. Test-drive the vehicle in 1st gear, with the shift lever in D, at speeds over 7 mph (12 km/h), and with the engine speed above 1,000 rpm, for at least 12 seconds.

-4. Monitor the OBD STATUS for P0731 in the DTCs MENU with the HDS.

Does the HDS indicate FAILED?
-YES- The failure is duplicated. Replace the 1st clutch or the transmission , then do the repair verification.
-NO- If the HDS indicates PASSED, intermittent failure, the system is OK at this time. If the HDS indicates NOT COMPLETED, test-drive again.

Repair verification (OBD STATUS check):

-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with the HDS.

-3. Test-drive the vehicle in 1st gear, with the shift lever in D, at speeds over 7 mph (12 km/h), and with the engine speed above 1,000 rpm, for at least 12 seconds.

-4. Monitor the OBD STATUS for P0731 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED, FAILED, or NOT COMPLETED?
-PASSED- Troubleshooting is complete. Check for other DTC after this troubleshooting. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 2 and recheck.
-NOT COMPLETED- Meet the test condition, and check the OBD STATUS again.