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.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0731 1st Gear Incorrect Ratio
      

1.
Problem verification:

Problem verification
?1.
Press the engine start/stop button to select the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Test-drive the vehicle in 1st gear in D, at speeds over 7 mph (12 km/h) for at least 12 seconds.

?4.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0731 1st Gear Incorrect Ratio
      

Is DTC P0731 indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time.?
2.
1st clutch pressure check:

1st clutch pressure check
?1.
Measure the 1st clutch pressure.

Is the 1st clutch pressure within the service limit?

     
YES
     
     
     
The 1st clutch pressure is OK. Faulty 1st clutch. Replace the 1st clutch or the transmission. If replacing the 1st clutch, clean off any metal debris or excessive clutch material inside the transmission, the ATF cooler, the ATF hoses, the ATF pipes, and the hydraulic circuit. Then, replace the 1st clutch and the torque converter.?
     
NO
     
     
     
Go to step 3.
3.
1st clutch hydraulic circuit check:

1st clutch hydraulic circuit check
?1.
Measure the line pressure.

Is the line pressure within the service limits?

     
YES
     
     
     
Clogged 1st clutch hydraulic circuit. Clean the 1st clutch hydraulic circuit, or replace the transmission. If cleaning the 1st clutch hydraulic circuit, clean off any metal debris or excessive clutch material inside the transmission, the ATF cooler, the ATF hoses, the ATF pipes, and the hydraulic circuit. Then, replace the torque converter.?
     
NO
     
     
     
The 1st clutch hydraulic circuit is OK. Faulty ATF pump or main regulator valve. Replace the main valve body (ATF pump), the regulator valve body (main regulator valve), or the transmission. If replacing the main valve body or the regulator valve body, clean off any metal debris or excessive clutch material inside the transmission, the ATF cooler, the ATF hoses, the ATF pipes, and the hydraulic circuit. Then, replace the main valve body or the regulator valve body and the torque converter.?