DTC Troubleshooting: P0734
DTC P0734: 4th 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
P0734 4th 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 4th gear in D for at least 12 seconds.

?4.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P0734 4th Gear Incorrect Ratio
      

Is DTC P0734 indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time.?
2.
4th clutch pressure check:

4th clutch pressure check
?1.
Measure the 4th clutch pressure.

Is the 4th clutch pressure within the service limit?

     
YES
     
     
     
The 4th clutch pressure is OK. Faulty 4th clutch. Replace the 4th clutch or the transmission. If replacing the 4th 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 4th clutch and the torque converter.?
     
NO
     
     
     
Go to step 3.
3.
4th clutch hydraulic circuit check:

4th clutch hydraulic circuit check
?1.
Measure the line pressure.

Is the line pressure within the service limits?

     
YES
     
     
     
Clogged 4th clutch hydraulic circuit. Clean the 4th clutch hydraulic circuit, or replace the transmission. If cleaning the 4th 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 4th 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.?