What Does P0631 Mean?
The VIN stored in the TCM (Transmission Control Module) does not match the vehicle or has not been programmed. The TCM uses the VIN for proper shift calibration selection and to ensure the correct transmission strategy is applied. This code typically appears after TCM replacement or reprogramming errors.
Common Causes
45%
TCM replaced without proper VIN programming
25%
Used/salvage TCM installed with wrong VIN stored
20%
TCM EEPROM corruption affecting VIN storage area
10%
Failed TCM reflash procedure that cleared VIN data
Diagnostic Steps
1
Step 1: Use a factory-level scan tool to read the VIN stored in the TCM and compare to the vehicle's VIN — they must match exactly.
2
Step 2: If the VIN does not match or is blank, program the correct VIN using the manufacturer's TCM programming procedure.
3
Step 3: Verify the TCM part number is correct for this vehicle and transmission combination before reprogramming.
4
Step 4: After VIN programming, clear codes and perform a transmission adaptive relearn drive cycle as specified by the manufacturer.
5
Step 5: If the VIN cannot be written, the TCM EEPROM is damaged and a new TCM is needed.
Estimated Repair Cost
$100 - $1,400
Parts + labor, varies by vehicle and location
The VIN stored in the TCM (Transmission Control Module) does not match the vehicle or has not been programmed. The TCM uses the VIN for proper shift calibration selection and to ensure the correct transmission strategy is applied. This code typically appears after TCM replacement or reprogramming er...
The most common cause of P0631 (VIN Not Programmed or Incompatible – TCM) is: TCM replaced without proper VIN programming
Typical repair costs for P0631 range from $100 to $1,400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Transmission may use incorrect shift calibration, causing harsh shifts, delayed engagement, or limp mode. Vehicle is generally drivable but should be corrected promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0631 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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