Restricted fuel supply, such as a blocked fuel filter or a clogged pick-up strainer; Worn or sticking fuel injector or injectors delivering less than commanded; Low fuel pressure from a weak high-pressure or low-pressure fuel pump; Fuel pressure regulator, metering valve or rail pressure control fault; Wiring or connector fault in the injector or fuel pressure sensor circuits; Contaminated or poor-quality fuel, or air in the fuel system; Outdated or faulty engine control unit calibration, where the manufacturer has issued a known update.

P026C

Fuel Injection Quantity A Lower Than Expected.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
6C: FaultThe specific fault in that area

What it means

P026C means the engine control unit has found that the fuel actually being delivered (injection quantity, bank or system 'A') is lower than the quantity it commanded. It reaches this conclusion by comparing the requested fuel quantity with feedback such as fuel rail pressure, injector correction values, air-fuel ratio or engine speed behaviour. The exact monitoring method and what 'A' refers to depend on the make, engine and whether it is petrol or diesel.

Symptoms

Engine management warning light on
Loss of power or flat acceleration
Hesitation or poor throttle response
Rough running or misfire at idle
Hard starting or long cranking
Poor fuel economy or the engine going into limp mode

Possible causes

Restricted fuel supply, such as a blocked fuel filter or a clogged pick-up strainerlikely
Worn or sticking fuel injector or injectors delivering less than commandedlikely
Low fuel pressure from a weak high-pressure or low-pressure fuel pumplikely
Fuel pressure regulator, metering valve or rail pressure control faultpossible
Wiring or connector fault in the injector or fuel pressure sensor circuitspossible
Contaminated or poor-quality fuel, or air in the fuel systempossible
Outdated or faulty engine control unit calibration, where the manufacturer has issued a known updaterare

How to diagnose

Read all stored and pending codes and note the freeze frame data (load, rpm, fuel pressure, temperature) to see when the fault occurs.
Check for related codes covering fuel pressure, injector circuits, misfires or fuel trim, and diagnose those first if present.
Inspect the fuel level and fuel quality, and look for signs of contamination, water or the wrong fuel type.
Visually inspect wiring and connectors at the injectors, fuel pressure sensor and regulator or metering valve for damage, corrosion or chafing.
Check the service history for the last fuel filter change, and inspect the filter and fuel lines for restrictions, leaks or air ingress.
Using live data, compare commanded and actual fuel pressure and review injector correction or fuel trim values at idle and under load.
Measure low-pressure and high-pressure fuel supply against the manufacturer's specification for the engine.
Run injector balance or leak-off tests as the engine type allows, and check for any applicable calibration updates for the vehicle.

How to fix

Replace the fuel filter and clear any blockage in the fuel supply line or pick-up.
Replace or professionally recondition faulty injectors, and code or adapt new ones as the manufacturer requires.
Repair or replace the failing fuel pump or pressure control component.
Repair damaged wiring or connectors in the affected circuits.
Drain and replace contaminated fuel, then bleed the system as required.
Apply a manufacturer calibration update only if one is documented for this fault.

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but it should be fixed soon. Low fuel delivery can lead to a lean condition, hesitation, stalling or further damage, so avoid heavy loads and long journeys, and stop if it loses power badly or runs roughly.

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