Short to voltage on the throttle/fuel inhibit signal wire, often from chafed insulation or a pinched harness; Failed throttle actuator control module or electronic throttle body with an internal short; Corroded or loose electrical connector at the throttle body, pedal position sensor, or PCM; Open ground circuit for the inhibit circuit, causing the PCM to see a high voltage on the signal line; Faulty PCM driver for the inhibit circuit, though this is less common than wiring issues; Aftermarket accessories or alarm systems improperly tapped into the throttle or fuel circuit

DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P2555

P2555Throttle/Fuel Inhibit Circuit High

Q: What does code P2555 mean?

Throttle/Fuel Inhibit Circuit High. P2555 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the throttle/fuel inhibit circuit, which is used to cut fuel or throttle during certain safety or traction-control events. The circuit is typically a low-current control line that the PCM monitors for expected voltage; a high reading means the wire is shorted to power, the ground reference is lost, or the component receiving the signal has failed internally.

P2555 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the throttle/fuel inhibit circuit, which is used to cut fuel or throttle during certain safety or traction-control events. The circuit is typically a low-current control line that the PCM monitors for expected voltage; a high reading means the wire is shorted to power, the ground reference is lost, or the component receiving the signal has failed internally.

SystemPowertrain

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reduced engine power or limp mode, where the throttle responds sluggishly or not at all
The engine may stall or refuse to start because fuel delivery is inhibited
Traction control or stability control warning lights may also come on if the systems share the circuit
Intermittent hesitation or surging if the fault is a loose connection rather than a hard short

Common causes, most likely first

Short to voltage on the throttle/fuel inhibit signal wire, often from chafed insulation or a pinched harness
Failed throttle actuator control module or electronic throttle body with an internal short
Corroded or loose electrical connector at the throttle body, pedal position sensor, or PCM
Open ground circuit for the inhibit circuit, causing the PCM to see a high voltage on the signal line
Faulty PCM driver for the inhibit circuit, though this is less common than wiring issues
Aftermarket accessories or alarm systems improperly tapped into the throttle or fuel circuit

How to diagnose and fix it

Scan all modules for stored and pending codes, and record freeze-frame data to see when the fault occurred
Visually inspect the throttle body, pedal assembly, and PCM connectors for corrosion, loose pins, or chafed wiring
Use a digital multimeter to measure voltage on the inhibit circuit at the component and at the PCM, comparing to manufacturer specifications
Perform a wiggle test on the harness while monitoring the signal voltage to reveal intermittent shorts
Disconnect the component and check for a short to voltage on the signal wire with the key on and the PCM disconnected
If wiring and connectors are good, substitute a known-good throttle body or actuator and recheck for the code
Clear codes and perform a throttle relearn or idle relearn procedure as required after repairs

Why a high voltage code is not always the throttle body

A shorted or chafed harness section near the exhaust manifold or under the battery tray is a frequent culprit that mimics a failed throttle body.
The inhibit circuit often shares a ground with other sensors, so a bad ground elsewhere can set P2555 without any fault in the throttle system itself.
Aftermarket remote starters or alarm systems that tap into the fuel pump or throttle wiring can introduce a high-voltage bias that the PCM interprets as a fault.
A weak or failing battery can cause the PCM to log this code during cranking if voltage spikes on the inhibit line, so always check charging system health first.
Replacing the throttle body without checking the ground circuit is a common misdiagnosis that leads to repeat failures and unnecessary expense.

Can I keep driving with P2555?

Do not continue driving with P2555 because the fault can cause the engine to stall or enter limp mode without warning, which is unsafe in traffic. Have the vehicle towed to a repair shop or diagnose it immediately in a safe location before attempting further driving.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.