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:
-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 ATF Replacement 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 Automatic Transmission Removal And Installation, then do the repair verification.
-NO- Replace the ATF ATF Replacement, then go to step 2.
2. Stall speed check:
-1. Test the stall speed in D A/T Stall Speed Test.
Is the stall speed rpm within the service limits?
-YES- The stall speed rpm is OK. Go to step 3.
-NO- Shift valves A and D are stuck. Repair the hydraulic system related with shift valves A and D, or replace the main valve body (shift valve A), the servo body (shift valve D), or the transmission Automatic Transmission Removal And Installation, then do the repair verification.
3. Line pressure check:
-1. Measure the line pressure A/T Pressure Test.
Is the line pressure within the service limit?
-YES- The 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 Automatic Transmission Removal And Installation, then do the repair verification.
4. 1st clutch pressure check:
-1. Measure the 1st clutch pressure A/T Pressure Test.
Is the 1st clutch pressure within the service limits?
-YES- The 1st clutch pressure is OK. Go to step 5.
-NO- Shift valves B and C are stuck. Repair the hydraulic system related with shift valves B and C, or replace the main valve body (shift valves B and C) or the transmission Automatic Transmission Removal And Installation, then do the repair verification.
5. Problem verification:
-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 FAILED?
-YES- The failure is duplicated. Replace the 1st/3rd clutch or the transmission Automatic Transmission Removal And Installation, 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- Troubleshooting is incomplete. Check for poor connections or loose terminals between the input shaft (mainshaft) speed sensor, the output shaft (countershaft) speed sensor, and the PCM, then go to step 2 and recheck.
-NOT COMPLETED- Repair verification is incomplete. Meet the test condition, and check the OBD STATUS again.