P2554 Throttle/Fuel Inhibit A Circuit Low

P2554 reports that the voltage on throttle/fuel inhibit circuit A is too low. In GM's 2005 L66 parameter sheet the limit is below 0.498 V on the analogue inhibit circuit, read by the powertrain module while it is still processing after the ignition has been switched off. The table lists a warm engine, coolant at 69.5 °C or more, among the enable conditions. Since the check takes place after shutdown, the lamp lights on the next drive rather than at once. A low reading usually comes from a short to ground somewhere in the inhibit wiring or a pull-down inside a connected unit. The relay itself is judged under P2553, an over-voltage on the same line under P2555, and P2552 is the general circuit fault. Drivers may meet a throttle that reacts sluggishly or a reduced-power mode.

Likely causes

Symptoms

• Check engine light on the following drive
• Sluggish throttle response or reduced power

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: gsi.ext.gm.com, law.cornell.edu.