Fault code P0925 – gear shift reverse actuator circuit range/performance

Fault code P0925 is called “Gear Shift Reverse Actuator Circuit Range/Performance” 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 P0925

This diagnostic trouble code (DTC) is a generic transmission code. Error P0925 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 P0925 – gear shift reverse actuator circuit range/performance

Dual clutch transmissions and automated manual transmissions often use a shift actuator module (GSAM). The GSAM engages or disengages the clutch and selects a gear based on commands from the Transmission Control Module (TCM).

The gear selection solenoid actuates a valve that applies hydraulic pressure to move the gear selector shaft. Then, inside the transmission unit, the shift fork moves to the desired position.

In most cases, a shift solenoid is used to engage the gear, and a clutch solenoid is used to control the clutch. This process allows automatic gear shifting in the mechanical part of the transmission.

When the control module (TCM) detects an inconsistency in the operating range of the reverse gear shift actuator circuit. Fault code P0925 will be written to memory and an error message will appear on the control panel.

Symptoms of vehicle malfunctions

The main signal that an error P0925 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. The “Check engine” control lamp on the control panel will light up (the code will be stored as a fault).
  2. The transmission does not shift properly.
  3. The gears do not engage or shift.
  4. There may be no symptoms other than a stored fault code.

A stored fault code P0925 is considered serious, as it may result in handling and safety problems with the vehicle. The conditions that contributed to the stored code should be corrected as soon as possible.

Factors that can cause this error code

The error code P0925 can mean that one or more of the following problems have occurred:

  • Problem with forward shift actuator.
  • Faulty forward gear selection solenoid.
  • Shorted or damaged wiring harness.
  • Faulty wiring harness connector.
  • Transmission control module (TCM) may be defective.

How to fix or reset OBD-2 code P0925

Some suggested steps for troubleshooting and fix the error code P0925:

  1. Read all stored data and error codes with an OBD-II scanner.
  2. Clear the error codes from the computer memory.
  3. Test-drive the vehicle to see if error P0925 appears again.
  4. Visually inspect the appropriate wires and connectors for damage.
  5. Check the forward shift actuator.
  6. If necessary, replace the failed components.
  7. Test the transmission control module (TCM).

Diagnose and repair of problems

The first thing to do when diagnosing code P0925 is to check the electrical part for damage. In today’s vehicles, electrical and electronic signals require good cabling for proper data transmission.

Any faults, such as breaks, disconnected connectors or corrosion, can interrupt signals, leading to transmission control failures. Next, check the battery, as some PCM and TCM modules are sensitive to low voltage.

If the battery is low, the system may detect this as a failure. Check that the battery is delivering a minimum of 12 volts and that the alternator is operating properly, a minimum of 13 volts at idle.

If there are no malfunctions, you should check the gear selector and shift actuator. It usually fails due to moisture ingress and oxidation of the contacts.

The transmission control module (TCM) fails very rarely, so when diagnosing error P0925, it should be checked if all other checks have been done.

On which vehicles does this problem occur most frequently

Fault code P0925 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Citroen (C4, Picasso)
  • Mercedes-Benz
  • Peugeot

Fault code P0925 can sometimes be found with other errors. The most common are the following: P0924, P0926, P0927.


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