What it means
General electrical fault on the throttle/fuel inhibit input A. This input lets external safety functions (immobilizer, hybrid HV interlock, anti-theft) override the throttle or cut fuel delivery. With the input invalid the safety override is unreliable, so the ECM falls back to its safe default — typically inhibit asserted to err on the side of safety.
At a glance
- Usually lights the check-engine light
How it works
The throttle/fuel inhibit circuit A carries a safety request that can prevent throttle operation or fuel delivery, such as during an interlock or security event. The ECM monitors the circuit for a valid electrical state and sets P2552 when the input circuit has a general fault, so the safety request cannot be relied on.
Common causes
Most likely first.
- Open or shorted inhibit-circuit wiring
- Loose or corroded connector
- Faulty throttle/fuel inhibit switch or input
- Fault in a connected control module
Symptoms
- Check-engine light
- Engine may not start or may stall
- Reduced or unavailable throttle response
How to diagnose it
- Record freeze-frame data and check live data for throttle/fuel inhibit A to see whether the ECM reports an invalid state during a no-start, stall, or throttle complaint.
- Inspect the inhibit A wiring and connectors for an unplugged connector, corrosion, damaged terminals, or a short or break in the harness.
- Check related security or interlock warnings and scan connected modules for faults that could explain an active inhibit request.
- Use the wiring diagram to test the inhibit A circuit for continuity and shorts, following the manufacturer's specification.
- If the wiring and input device test correctly, compare the requesting module's state with the ECM's reported input to isolate a module fault.
Common fixes
- Reconnect or secure a loose throttle/fuel inhibit A connector.
- Clean corroded terminals and repair damaged connector pins.
- Repair an open or short in the inhibit A wiring.
- Replace a faulty inhibit switch or input device after confirming its circuit is sound.
- Repair the connected control module or its output if it sends an invalid inhibit state.
Can I keep driving?
If the engine will not start, stalls, or has little throttle response, do not rely on the vehicle for traffic or other situations requiring dependable acceleration. The fault can also make the safety inhibit function unreliable.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.