Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer that controls the transmission is having trouble communicating properly, like a phone call with a lot of static.
This code indicates that the Transmission Control Module (TCM) has detected an internal error where interference has exceeded the acceptable threshold.
The P172D code is triggered when the Transmission Control Module (TCM) detects a level 2 error due to interference, which means that the interference counter has reached a level of 4 or above, indicating significant disruption in the module's operation.
• Check Engine Light is on
• Transmission may not shift properly
• Reduced fuel efficiency
• Faulty Transmission Control Module
• Electrical interference in the TCM wiring
• Poor ground connection
Transmission Control Module (TCM): A computer that manages the operation of the transmission.
Interference: Disruption in electrical signals that can affect electronic components.
• Use an OBD-II scanner to confirm the code
• Inspect the TCM and its wiring for damage or loose connections
• Check for any signs of electrical interference or grounding issues
• Replace or repair the Transmission Control Module if faulty
• Fix any damaged wiring or poor connections
• Ensure proper grounding of the TCM
• OBD-II Scanner
• Multimeter
• Screwdriver set
$200 - $800
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regularly check and maintain electrical connections
• Avoid aftermarket electronic devices that may cause interference
• Ensure proper grounding of vehicle components
Transmission Control Module Issue
• Avoid driving at high speeds until the issue is resolved
• Consult a professional mechanic for a thorough diagnosis
Check with the vehicle manufacturer for warranty coverage on the Transmission Control Module.
This code has been associated with vehicles experiencing electrical interference issues, often due to poor grounding or faulty TCMs.
Moderate – It is advisable to address this issue soon to avoid potential transmission damage.
Driving with transmission issues can be unsafe. Address the problem promptly to ensure vehicle safety.
• Vehicle in park or neutral
• Engine running
The Transmission Control Module is typically located near the transmission or in the engine bay, depending on the vehicle model.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to transmission failure or further damage, resulting in costly repairs.
Q: Can I drive my car with this code?
A: It's best to limit driving until the issue is fixed, as it may affect transmission performance and safety.
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