Faulty low pressure fuel pressure sensor giving a false high reading; Fuel pressure regulator or pressure control valve stuck closed; Restricted fuel return line or blocked return path; Fuel pump control module or lift pump running at too high a speed or output; Wiring or connector fault on the sensor or pump circuit (short to voltage, high resistance); Fault in the high pressure pump inlet metering valve affecting supply side pressure; Engine control unit fault or outdated software calibration where a manufacturer bulletin applies.

P008B

Low Pressure Fuel System Pressure - Too High.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
0: AreaFuel and air metering, auxiliary emission controls
8B: FaultThe specific fault in that area

What it means

P008B is the generic code for low pressure fuel system pressure being too high. The engine control unit compares the low pressure (supply side) fuel pressure reported by its sensor with the target pressure, and sets the code when the measured value stays above the target by more than the allowed margin. This applies to direct injection and diesel systems that have a lift pump feeding a high pressure pump, and the exact strategy varies by model and engine.

Symptoms

Engine management light on
Hard or extended cranking before starting
Rough idle or hesitation under load
Reduced power or limp mode
Smell of fuel or fuel odour from the exhaust
Poor fuel economy

Possible causes

Faulty low pressure fuel pressure sensor giving a false high readinglikely
Fuel pressure regulator or pressure control valve stuck closedlikely
Restricted fuel return line or blocked return pathpossible
Fuel pump control module or lift pump running at too high a speed or outputpossible
Wiring or connector fault on the sensor or pump circuit (short to voltage, high resistance)possible
Fault in the high pressure pump inlet metering valve affecting supply side pressurerare
Engine control unit fault or outdated software calibration where a manufacturer bulletin appliesrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting engine load, temperature and fuel pressure at the time of setting
Check for related codes covering the fuel pump control module, rail pressure or sensor circuits, and deal with those first
Inspect the wiring and connectors at the low pressure fuel sensor, regulator and pump for damage, corrosion or water ingress
Compare live low pressure fuel pressure with the target value at idle and under load to see if the reading is consistently high or erratic
Check the sensor signal and supply voltage against the manufacturer's specification, and compare the key-on reading with ambient pressure
Measure actual fuel pressure with a suitable gauge at the test point, if the vehicle has one, and compare it with the sensor reading
Inspect the fuel return line and any in-line valves for kinks, blockage or damage
Command the fuel pump or regulator using the scan tool's active tests where available and watch the pressure response

How to fix

Replace the low pressure fuel pressure sensor if its reading disagrees with the measured pressure
Replace the fuel pressure regulator or pressure control valve if it is stuck or not responding
Clear or replace a blocked or damaged return line
Repair damaged wiring or connectors, or replace the pump control module if it is confirmed faulty
Replace the lift pump or high pressure pump metering components if testing shows they are at fault
Update the control unit software only where the manufacturer lists an outdated calibration as a known cause

Can I keep driving?

Medium severity

The car can usually be driven short distances, but high supply pressure can stress the fuel system and may lead to poor running or limp mode, so have it checked soon. Stop driving if it runs badly, smells strongly of fuel or leaks.

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