Injector over-delivering or leaking, so the engine needs less commanded fuel to idle; Fuel pressure higher than commanded, for example a faulty pressure regulator, pressure control valve or pressure sensor; Fuel diluting the engine oil, which adds to the engine's power output; Incorrect or missing injector correction data after an injector or control unit replacement; Faulty crankshaft or engine speed sensor, or a wiring or connector fault giving a wrong speed signal; Unmetered air or an intake fault on engines where this affects idle fuel calculation; Outdated control unit software where a manufacturer bulletin lists this code as a known issue.

P054E

Idle Control System - Fuel Quantity Lower Than Expected.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
5: AreaVehicle speed, idle control and auxiliary inputs
4E: FaultThe specific fault in that area

What it means

P054E is set when the engine control unit finds that the fuel quantity needed to hold the target idle speed is lower than the expected value. In other words, the engine is idling on less fuel than the control unit's model says it should need. The exact limits, and whether this is monitored per cylinder or for the whole engine, depend on the make, model and engine, so check manufacturer data for the vehicle.

Symptoms

Engine warning light on
Idle speed hunting, surging or sitting higher than normal
Rough or uneven idle
Black or blue-grey smoke at idle or on start-up
Higher than normal fuel consumption
Smell of fuel from the engine or oil

Possible causes

Injector over-delivering or leaking, so the engine needs less commanded fuel to idlelikely
Fuel pressure higher than commanded, for example a faulty pressure regulator, pressure control valve or pressure sensorpossible
Fuel diluting the engine oil, which adds to the engine's power outputpossible
Incorrect or missing injector correction data after an injector or control unit replacementpossible
Faulty crankshaft or engine speed sensor, or a wiring or connector fault giving a wrong speed signalpossible
Unmetered air or an intake fault on engines where this affects idle fuel calculationrare
Outdated control unit software where a manufacturer bulletin lists this code as a known issuerare

How to diagnose

Read all stored and pending codes with freeze frame data, noting engine temperature, load and speed when the code set, and look for related fuel, injector or sensor codes
Inspect the wiring, connectors and earths for the injectors, fuel pressure sensor and crankshaft sensor for damage, corrosion or fuel contamination
Check the engine oil level and smell and look for a rising level or thin, fuel-smelling oil that suggests dilution
Check for any visible fuel leaks and inspect the fuel system for signs of high pressure faults
Compare live data for commanded and actual fuel pressure, engine speed and per-cylinder correction values at idle, once the engine is fully warm
Check the live idle speed against the target and compare the engine speed sensor signal with a known good reading
Run any injector balance or contribution test the manufacturer specifies and compare cylinders
Check whether any injector, pump or control unit work has been done recently and that correction codes were entered, and look up manufacturer bulletins for the model

How to fix

Replace or repair any injector found to be leaking or over-delivering, and enter its correction data as the manufacturer specifies
Repair or replace the faulty fuel pressure regulator, control valve or pressure sensor
Cure the cause of fuel dilution and change the engine oil and filter
Repair damaged wiring or connectors, or replace a faulty crankshaft speed sensor
Re-enter or relearn injector correction values and carry out the manufacturer's adaptation procedure
Update the control unit software only if a manufacturer bulletin names it as the fix for this fault

Can I keep driving?

Medium severity

The car can usually be driven short distances, but get it checked soon. A leaking injector or fuel dilution of the oil can damage the engine if left, so stop driving if you see heavy smoke, a strong fuel smell or a rising oil level.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.