Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the computer in charge of controlling the part of the car that switches between two-wheel and four-wheel drive needs to be adjusted or reset.
The C12A6 code indicates an issue with the calibration of the Transfer Case Control Module (TCCM), which is responsible for managing the transfer case that switches between different drive modes.
The Transfer Case Control Module requires calibration to ensure accurate control of the transfer case. If the module is not properly calibrated, it may not correctly engage or disengage the four-wheel drive system, leading to potential drivability issues.
• Four-wheel drive not engaging
• Warning light on the dashboard
• Unusual noises from the transfer case
• Incorrect calibration of the TCCM
• Faulty TCCM
• Software issues or updates needed
Transfer Case: A part of the drivetrain that switches between two-wheel and four-wheel drive.
Calibration: The process of setting or correcting a device or system.
• Check for any software updates for the TCCM
• Perform a calibration procedure using a scan tool
• Inspect the wiring and connections to the TCCM
• Recalibrate the TCCM using a diagnostic scanner
• Replace the TCCM if faulty
• Update the TCCM software if necessary
• OBD-II scanner
• Diagnostic software
• Basic hand tools
$150 - $500
Moderate
• Chevrolet Silverado
• GMC Sierra
• Ford F-150
• Regularly check for software updates
• Perform routine maintenance on the transfer case
• Ensure proper usage of four-wheel drive modes
Control Module Issue
• Avoid using four-wheel drive until the issue is resolved
• Consult a professional mechanic for diagnosis and repair
Check with the vehicle manufacturer for warranty coverage on the TCCM.
This code has been associated with vehicles that frequently switch between drive modes, indicating the importance of regular calibration.
Moderate – It should be addressed soon to prevent potential drivability issues.
Driving with an improperly calibrated transfer case can lead to safety issues and should be corrected promptly.
• Vehicle parked on a level surface
• Ignition in the 'ON' position
The Transfer Case Control Module is typically located near the transfer case, under the vehicle.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to issues with engaging four-wheel drive, which can affect vehicle performance and safety.
Q: Can I fix this myself?
A: Recalibration often requires specialized diagnostic tools, so it's best handled by a professional mechanic.
Pro · Four-system diagnostics
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