Reverse Incorrect Gear Ratio

Reverse Incorrect Gear Ratio

Modern vehicles equipped with automatic transmissions / transaxles use a torque converter between the engine and transmission to increase the engine torque output and drive the rear wheels.

This code can show up in vehicles with an automatic transmission when there is a problem shifting into reverse gear, or while driving in reverse. The automatic transmission changes the output direction to move the vehicle in reverse and is most often controlled manually through hydraulic pressure even on computer controlled transmissions.

The Engine Control Module (ECM), Powertrain Control Module (PCM) or Transmission Control Module (TCM) uses input from various sensors to verify the correct operation of the transmission and its components. Engine speed is often calculated against the transmission speed sensor to determine gear ratio and torque converter slip. If the calculation does not match the desired value, the Diagnostic Trouble Code is set and the Check Engine Lamp is illuminated. Incorrect ratio codes typically require an advanced mechanical ability and diagnostic tools.

Note: This code is similar to P0730, P0730, P0731, P0732, P0733, P0734 and P0735. If there are other transmission codes, repair those problems first before proceeding with an incorrect gear ratio code.