Fault code P0736 – reverse incorrect gear ratio

Fault code P0736 is called “Reverse Incorrect Gear Ratio” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P0736

This diagnostic trouble code (DTC) is a generic transmission code. Error P0736 is considered a general code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.

Fault code P0736 – reverse incorrect gear ratio

This code may appear in vehicles with automatic transmission. When there is a problem shifting into or out of reverse gear. The computer-controlled automatic transmission uses multiple gear ratios. To increase vehicle speed while maximizing engine output.

Newer cars may have more than four gear ratios to improve fuel economy. The computer determines when to shift up or down based on throttle position and vehicle speed.

The engine control module (ECM), transmission control module (PCM) or (TCM) uses input from various sensors. To verify that the transmission and its components are working properly. Engine speed is often calculated from the transmission speed sensor to determine torque converter ratio and slip.

If the calculation does not match the desired value, a P0736 OBD2 diagnostic trouble code is set and the engine check lamp illuminates. Incorrect ratio codes, usually require a mechanical as well as diagnostic scanner check.

Symptoms of vehicle malfunctions

The main signal that an error P0736 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. Check engine control lamp on the control panel will light up (the code will be recorded in the ECM memory as a fault).
  2. Delayed shift or no shift into reverse gear.
  3. Slipping of automatic transmission.
  4. Increased fuel consumption.
  5. Sometimes drivers may not notice any signs of this error.

Factors that can cause this error code

The error code P0736 can mean that one or more of the following problems have occurred:

  • Low level or dirty ATF transmission fluid.
  • Clogged transmission fluid passages.
  • Mechanical transmission failure.
  • Blockage inside main transmission regulator.
  • Faulty shift solenoid.
  • Damaged or defective PCM module.

How to fix or reset OBD-2 code P0736

Some suggested steps for troubleshooting and fix the error code P0736:

  1. All damaged circuits and system connectors should be checked, repaired or replaced.
  2. Replace any damaged or malfunctioning components inside the transmission.
  3. Check and, if necessary, replace faulty PCM.
  4. If the problem is low or contaminated ATF transmission fluid, the fluid should be topped up or replaced.

You should also pay attention to other error codes. Which may have appeared along with code P0736. They may help to determine which parts need to be repaired or replaced.

Diagnose and repair of problems

Be sure to check the level and condition of the ATF fluid before continuing with the diagnosis of fault P0736. Incorrect fluid level or dirty fluid can cause shifting problems. Affecting the operation of multiple gears.

Transmission clutches are usually controlled by a solenoid or fluid pressure. If there is an electrical problem with the shift solenoid. A code related to this problem should be displayed. Have the electrical problem corrected before proceeding.

Clogged ducts interfere with fluid circulation within the transmission, which can also cause error P0736. If there are several codes with gear ratio errors, but the transmission is working properly. There may be a mechanical problem with the torque converter, main transmission control, or pressure issues.

It may be necessary to use a diagnostic scanner to determine which gear the transmission is controlling. And determine if the engine speed matches the calculated output speed from the transmission sensor.

To troubleshoot this type of problem, knowledge of transmission operation and overhaul is often required. Refer to the factory service manual for specific vehicle diagnostic procedures.

On which vehicles does this problem occur most frequently

Fault code P0736 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Audi
  • BMW
  • Chrysler (Town and Country)
  • Dodge (Caravan, Charger, Stratus)
  • Ford
  • Jeep (Liberty)
  • Land Rover (Discovery, Range Rover)
  • Mitsubishi (Endeavor)
  • Ssangyong
  • Subaru

Fault code P0736 can sometimes be found with other errors. The most common are the following: P0730, P0731, P0732, P0733, P0734, P0735.


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