Throttle/Fuel Inhibit Circuit High
The P2555 code means the vehicle's onboard diagnostic system has detected: Throttle/Fuel Inhibit Circuit High. This is a critical severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $800 (parts and labor)
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Common Symptoms
- Inhibit system cannot activate when needed
- Safety override disabled
- Check engine light on
- Vehicle may operate normally until fault condition occurs
Probable Causes (Ranked by Likelihood)
- Short to voltage in inhibit circuit Very High
- Inhibit relay contacts welded closed High
- Wiring harness damage providing constant power Moderate
- ECM inhibit driver output stuck high Low
Frequently Asked Questions
Is P2555 dangerous even though the car drives fine?
Yes. The inhibit circuit is a safety system. If it cannot activate when needed, the ECM cannot limit throttle during a detected fault, potentially allowing unintended acceleration.
What happens if the inhibit circuit cannot engage?
If a throttle fault occurs, the ECM would normally cut throttle and fuel. With P2555, this safety response may not function, creating a potential safety hazard.
Should I drive with P2555?
Only short distances at low speeds to reach a repair shop. The safety override system is compromised and should be repaired as soon as possible.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Check inhibit circuit for constant voltage condition
-
Test inhibit relay for welded contacts
-
Inspect wiring for short to power source
-
Verify ECM can command inhibit circuit low
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2010-2020 Toyota Camry
- 2012-2019 Nissan Maxima
- 2008-2018 Ford Fusion
- 2011-2020 Chevrolet Impala
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