The OBD-II code P0904 refers to a problem with the Gate Select Position Circuit in vehicles equipped with manual transmissions. This code is triggered when the engine control module (PCM) receives an implausible signal from the Shift Lever Position Sensor, which indicates that the transmission is not in the expected gear.
What Does the P0904 Code Mean?
The P0904 code is a diagnostic trouble code (DTC) that indicates an issue with the manual transmission’s gate select position circuit. This circuit is responsible for communicating the current gear position of the transmission to the PCM. If the PCM detects an inconsistent or incorrect signal from the shift lever position sensor, it will store the P0904 code.
What Causes the P0904 Code?
There are several potential causes for the P0904 code, including:
- Failure of the shift lever assembly
- Transmission Control Module (TCM) failure
- Wiring issues or damaged connections
What Are the Symptoms of the P0904 Code?
Symptoms associated with the P0904 code may include:
- Transmission not shifting correctly
- Warning lights on the dashboard
- Difficulty in engaging gears
How Serious Is the P0904 Code?
The P0904 code is classified as urgent because it indicates a significant malfunction that can lead to severe damage to the vehicle or pose safety risks to the driver and passengers. Immediate attention is recommended to avoid further complications.
How to Diagnose the P0904 Code
To diagnose the P0904 code, a mechanic will typically perform the following steps:
- Use an OBD-II scanner to confirm the presence of the P0904 code and check for any other related codes.
- Inspect the wiring and connectors related to the shift lever position sensor for any damage or disconnections.
- Test the shift lever position sensor’s functionality to determine if it is operating correctly.
- Evaluate the shift lever assembly and TCM for any signs of failure.
Common Repairs for the P0904 Code
Common repairs that may be necessary for the P0904 code include:
- Replacing the shift lever assembly
- Repairing or replacing damaged wiring or connectors
- Replacing the Transmission Control Module (TCM) if it is found to be faulty
How Much Does It Cost to Fix the P0904 Code?
The cost to fix the P0904 code can vary widely depending on the specific issue and the vehicle make and model. Repair costs may range from $100 to $1,500, depending on whether parts need to be replaced or if extensive labor is required.
Can I Fix the P0904 Code Myself?
While some DIY enthusiasts may feel comfortable troubleshooting and fixing wiring issues or replacing components like the shift lever assembly, it is often recommended to consult with a professional mechanic. Proper diagnosis is crucial as simply replacing parts without understanding the underlying issue may not resolve the problem.
