What Does P1631 Mean?
This code indicates either a theft deterrent system communication failure or an issue with the B+ power supply to the vehicle control and radio module A/C circuit. The dual definition suggests manufacturer-specific implementation varies.
Common Causes
30%
Anti-theft system communication failure with PCM
25%
Power supply issue to vehicle control module or radio module
20%
Wiring or connector damage between security system and PCM
15%
Faulty vehicle control module or radio control module
10%
Battery voltage too low or charging system fault
Diagnostic Steps
1
Step 1: Check battery voltage and charging system output (should be 13.5-14.5V running)
2
Step 2: Inspect fuses related to body control module, radio, and security systems
3
Step 3: Test for B+ voltage at vehicle control module connector
4
Step 4: Scan all modules for communication codes and verify security system operation
5
Step 5: Check ground connections at affected modules for high resistance
Estimated Repair Cost
$100 - $1,000
Parts + labor, varies by vehicle and location
This code indicates either a theft deterrent system communication failure or an issue with the B+ power supply to the vehicle control and radio module A/C circuit. The dual definition suggests manufacturer-specific implementation varies.
The most common cause of P1631 (Theft Deterrent Fuel Enable Signal Not Received/ B+ Supply To VCRM A/C Circuit Malfunction) is: Anti-theft system communication failure with PCM
Typical repair costs for P1631 range from $100 to $1,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May prevent vehicle starting or cause starting issues. If vehicle runs, generally safe to drive but address soon to avoid being stranded.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1631 to identify the root cause.
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Quick Info
Category
Powertrain
System
Anti-theft/Electrical System
Difficulty
Type
Manufacturer
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