P0734 - GEAR 4 INCORRECT RATIO

The DTC code P0734 OBD2 is stored in vehicles with automatic transmissions due to problems shifting to or driving in gear number 4. The automatic transmission controlled by the vehicle’s computer uses multiple gear ratios to get higher vehicle speed while maximizing engine output.

The transmission ratio is the difference between the input speed and the output speed. Generally, there are speed sensors on the input and output of the transmission. The ECM (Engine Control Module) uses these sensors to compare speeds and make sure the gear ratio is right. If the ECM determines that the transmission ratio is out of the specified value, the DTC code P0734 is set.

• Check Engine lighting.
• Lack of power.
• Erratic transmission changes.
• The transmission slides.
• Transmission changes are hard.

The reasons why the diagnostic code P0734 OBDII is stored are the following:

• Transmission fluid contamination.
• Low transmission fluid level.
• The transmission is leaking oil.
• Low oil pressure.
• Corroded Transmission Control Module (TCM) cables
• Faulty TCM.

When faced with the fault code P0734 OBD2, you must do the following:

• Check both the condition of the transmission fluid as well as its level. Change it if necessary.
• Change transmission cables or connectors that are in bad condition.
• There is a solenoid that controls the clutches and bands. Make sure the solenoid's electrical circuitry is working properly. If you find problems, repair or replace it.