P1631: Theft Deterrent Start Enable Signal Not Correct/ Main Relay Malfunction (Power Hold)
HighPowertrainEngine/Powertrain
What does P1631 mean?
P1631 is a diagnostic trouble code indicating "Theft Deterrent Start Enable Signal Not Correct/ Main Relay Malfunction (Power Hold)". A component in the engine/powertrain has been flagged as malfunctioning by the vehicle's ECU. This requires diagnosis to determine whether the part itself has failed or if there is a related wiring or control issue.
Common causes
- Faulty engine/powertrain component
- Wiring or connector issue in the related circuit
- Failed sensor providing incorrect readings
- Software/calibration issue requiring ECU update
- Related component causing secondary fault
What should you do?
This is a significant issue that should be diagnosed and repaired soon. Avoid long trips or heavy driving until the problem is resolved. Continued driving may cause additional damage.
Get a diagnosis for YOUR car
Code P1631 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.