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DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P008B

P008BLow Pressure Fuel System Pressure - Too High

P008B indicates that the powertrain control module has detected a fuel pressure reading in the low-pressure fuel system that is higher than the expected value for the current operating conditions. The computer compares the actual pressure sensor signal against a commanded or modeled pressure and sets this code when the measured pressure exceeds the upper threshold for a calibrated time.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • A rich fuel mixture smell or black smoke from the exhaust
  • Rough idle or engine stumbling due to excessive fuel delivery
  • Reduced fuel economy as the engine receives more fuel than needed
  • Possible hard starting or flooding condition when the pressure remains too high
  • In some cases, a fuel pressure warning message on the dashboard

Common causes, most likely first

  1. Faulty low-pressure fuel pressure sensor sending an inflated reading
  2. Restricted fuel return line or a stuck-closed return valve causing pressure to build
  3. Malfunctioning fuel pressure regulator that fails to bleed off excess pressure
  4. Kinked or blocked fuel return hose from the low-pressure pump assembly
  5. Wiring issue such as a short to voltage or poor ground in the pressure sensor circuit
  6. Contaminated or sticking fuel pressure control solenoid in the low-pressure circuit
  7. Rarely, a powertrain control module calibration error or internal fault

How to diagnose and fix it

  1. Connect a scan tool and verify the low-pressure fuel pressure sensor reading against a mechanical gauge
  2. Inspect the fuel pressure sensor connector and wiring for corrosion, chafing, or shorts
  3. Check the fuel return line for restrictions, kinks, or a blocked return orifice
  4. Test the fuel pressure regulator for proper operation and replacement if it fails to regulate
  5. Measure the resistance of the fuel pressure control solenoid and compare to specification
  6. Perform a fuel system pressure bleed-down test to confirm the fault is mechanical versus electrical
  7. If all components test good, reprogram or replace the powertrain control module as a last resort

When the sensor lies about pressure

  • A skewed fuel pressure sensor is the most common cause of P008B, and it can report high pressure even when a mechanical gauge shows normal readings, leading to unnecessary replacement of good pumps and regulators.
  • A restricted fuel return line often mimics a failed pressure regulator, so technicians who replace the regulator without checking return flow frequently see the code return within a few drive cycles.
  • This code can be set by a fuel pressure sensor circuit that is shorted to voltage, which adds a false offset to the signal and makes the computer believe pressure is higher than it truly is.
  • On some vehicles, a fuel pressure control solenoid that sticks closed during deceleration or idle will cause momentary pressure spikes that are large enough to set P008B without any driveability complaint.
  • P008B does not always mean the low-pressure pump is faulty; a pump that delivers too much volume at low demand can also push pressure above the expected threshold, especially if the return path is undersized.

Can I keep driving with P008B?

You can usually drive the vehicle to a repair shop, but avoid aggressive acceleration or heavy loads because excess fuel pressure can cause rich running, fouled spark plugs, and potential damage to the catalytic converter over time. If you notice strong fuel odors or black smoke, stop driving and have the vehicle towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

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