Theft Deterrent System Fuel Enable Signal Not Received

What it means

This is a Chevrolet (GM) manufacturer-specific code, and the same number can mean something different on other makes. The engine computer (PCM) did not receive the message from the theft deterrent system (Passlock or PASS-Key) that allows it to enable the injectors, so it prevents starting or shuts the engine off after a few seconds. The most common cause is a failed Passlock sensor in the ignition lock cylinder, or poor key pellet contact on PASS-Key systems.

Models covered: Chevrolet (GM) models with Passlock/PASS-Key theft deterrent, mainly 1990s–2000s.

Related codes: P1631U1000P0562P1682

Symptoms4

• The engine starts, then dies after a few seconds.
• The engine cranks but does not start, or does not crank on some systems.
• Security or theft light on the dash is on or flashing.
• An intermittent fault that happens on some starts but not others.

Possible causes6

• A failed Passlock sensor in the ignition lock cylinder or broken wires in the steering column.
• A worn resistor pellet in the key or poor pellet contact in the cylinder on PASS-Key systems.
• A worn ignition lock cylinder.
• A weak battery or low voltage during cranking.
• A Class 2 data bus communication fault between the theft module and the engine computer.
• A body control module (BCM) or theft module fault (less common).

How to diagnose5

1. Read codes from the engine computer and from the body or theft module, as their codes point to the fault.
2. Note the security light at start-up and how the engine behaves: starts and dies, or no crank.
3. Check battery voltage and terminals.
4. Inspect the Passlock sensor wiring in the steering column, or measure the key pellet resistance on PASS-Key and compare it with specification.
5. Confirm the engine computer and theft module communicate on the Class 2 bus.

How to fix5

1. Charge or replace a weak battery.
2. Perform the known GM timed relearn procedure per the service manual.
3. Repair the Passlock sensor wiring in the column, or replace a damaged PASS-Key key.
4. Replace the lock cylinder or sensor if confirmed faulty, then perform the relearn.
5. Clear the codes, start the engine several times and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

Sometimes a relearn or a wire repair is enough, while a new lock cylinder or module with programming puts the cost at the top of the range.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions