P1626 on Chevrolet: How to Diagnose & Fix
Theft Deterrent Fuel Enable Signal Lost
2 Chevrolet models · 2 documented issues · 2 critical · $100-$900 repair
P1626 on Chevrolet by model: symptoms, diagnosis and fix
Early C5s use an electronic Column Lock mechanism as part of the anti-theft system (fitted to 1997-2004 manual cars and 1997-2000 automatics). The mechanism and its electronics fail with age; when the column fails to unlock at key-on the PCM disables fuel and the car will not drive (or displays 'Service Column Lock'/'Pull Key, Wait Ten Seconds' on the DIC). In some cases the column can lock unexpectedly. It is one of the best-known early-C5 gremlins and is the subject of GM service bulletins and a recall/special policy.
Common Symptoms
- No-crank / no-start or limp (~2 mph) condition
- Steering wheel remains locked
- 'Service Column Lock' / 'Pull Key Wait Ten Seconds' DIC message
- Intermittent failure to start
- Column unexpectedly locking
How to Fix
Modern accepted fix is to install an electronic column-lock bypass module or the GM relay fix (removes the failure-prone lock function) rather than sourcing the increasingly scarce factory lock assembly. Note on 1997-1998 cars the GM harness/relay is often more BCM-compatible than some aftermarket bypass modules. A BCM reset (pull the relevant fuse ~10 seconds) can temporarily clear the condition.
Sources for this issue (1)
The Passlock anti-theft system causes intermittent no-start conditions where the security light flashes and the fuel pump is disabled. The ignition lock cylinder contains a Hall-effect sensor that reads a resistance value; when contacts wear or corrode, the BCM detects a mismatch and locks out fuel delivery. The problem typically worsens progressively from occasional to daily. 225+ complaints were filed for the 2002 model year alone.
Common Symptoms
- Security/theft light flashing on dashboard
- Engine cranks but will not start
- No-start condition occurs more frequently over time
- Car starts after waiting 10+ minutes
- SECURITY telltale illuminated
How to Fix
Sources for this issue (1)
P1626 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1626 mean on a Chevrolet?
P1626 stands for "Theft Deterrent Fuel Enable Signal Lost." This is a manufacturer-specific (commonly GM) anti-theft code indicating that the fuel-enable signal from the theft-deterrent system was lost or not received by the engine control module. As a security measure, the immobilizer or body control module must send a valid signal authorizing the ECM to deliver fuel; without it, the ECM disables fueling so a stolen vehicle cannot be driven. The result is usually an engine that cranks but will not start, often with a security light on. It generally points to a security-system communication or authentication problem rather than a fuel or engine mechanical fault. On Chevrolet it is documented across 2 models: Corvette, Impala.
What are the most common causes of P1626?
The most common causes of P1626 are: Communication fault between the body control module and ECM, Faulty or unrecognized key/transponder or immobilizer issue, Damaged wiring or connectors in the theft-deterrent circuit, Faulty body control module (BCM), Faulty or improperly programmed engine control module, Loss of power or ground to a security-system module, Modules not properly relearned after a battery or part replacement. The specific cause varies by vehicle.
How much does it cost to fix P1626 on a Chevrolet?
Published repair estimates on Chevrolet range from $100 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P1626 on a different make?
View P1626 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.