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 found a problem with the transmission, which is the part that helps the car change gears. Because of this, the car might not drive like normal and could be in a special mode to protect itself.
This code indicates that the Transmission Control Module (TCM) has detected an internal error that affects its ability to control the transmission properly.
The P1931 code is triggered when the Transmission Control Module detects a Level 2 error in its internal monitoring systems. This error is significant enough to cause the TCM to enter a 'limp home' mode, where the transmission is restricted to prevent further damage.
• Vehicle stuck in one gear
• Reduced power or performance
• Transmission warning light on the dashboard
• Faulty Transmission Control Module
• Software glitch in the TCM
• Electrical issues such as poor connections or damaged wiring
Transmission Control Module (TCM): A computer that controls the automatic transmission in a vehicle.
Limp Home Mode: A safety feature that limits a vehicle's performance to prevent damage.
• Use an OBD-II scanner to confirm the code.
• Inspect the TCM for any visible damage or loose connections.
• Check the wiring and connectors related to the TCM.
• Reset the TCM and clear the code to see if it returns.
• Repair or replace any damaged wiring or connectors.
• Replace the Transmission Control Module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$300 - $1200
Moderate
• Ford Focus
• Mazda 3
• Chevrolet Malibu
• Regularly update vehicle software.
• Perform routine maintenance checks.
• Ensure electrical connections are secure.
Transmission Control Issue
• Avoid driving the vehicle until the issue is resolved.
• Consult a professional mechanic for a thorough diagnosis.
Check if the vehicle's transmission system is still under warranty, as this could cover repairs.
This code has been associated with vehicles that have electronic transmission controls, becoming more common as vehicles have advanced.
High – This issue can lead to significant transmission problems if not addressed promptly.
Driving with a malfunctioning transmission can be dangerous and may lead to further damage or legal issues if the vehicle fails to operate safely.
• Vehicle in 'limp home' mode
• Transmission warning light illuminated
The Transmission Control Module is usually located inside the transmission or mounted on the transmission housing.
Q: Can I drive with a P1931 code?
A: It's not recommended to drive with this code active, as it indicates a serious transmission issue.
Q: Will resetting the TCM fix the problem?
A: Resetting may temporarily clear the code, but if the underlying issue isn't fixed, the code will likely return.
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