Fuel and air

P009D — Fuel Pressure Relief Control Circuit High

Severity: medium Drive with care, to a shop

What P009D means

The engine control module operates a fuel pressure relief valve in the high-pressure fuel system and monitors the voltage in its control circuit. P009D sets when that voltage is higher than expected. Common causes are wiring or connector faults, a failed valve, or rarely the control module itself. As a result, rail pressure may not be regulated correctly.

Symptoms

  • Check Engine Light on
  • Reduced engine power
  • Hard starting or long cranking
  • Stalling or hesitation under load
  • Increased fuel consumption
  • Possible fuel smell in the engine bay

Possible causes

  1. Damaged wiring or corroded connector at the pressure relief valve
  2. Faulty fuel pressure relief valve
  3. Faulty pressure regulator or volume control valve
  4. Faulty fuel rail pressure sensor
  5. Worn or faulty high-pressure fuel pump
  6. Low-pressure supply problem (pump, filter, lines)
  7. Failed PCM (rare)

How to diagnose

  1. Read all codes and freeze frame data, and note any other fuel pressure codes
  2. Inspect the harness and connectors at the valve for damage, corrosion and chafing
  3. Check power and ground at the valve connector and test the wire to the PCM for a short to voltage
  4. Measure the valve coil resistance and compare it to specification
  5. Compare commanded and actual rail pressure during cranking, idle and under load
  6. Verify low-pressure fuel supply pressure and volume first
  7. Command the valve with a scan tool to confirm it responds
  8. Where applicable, measure injector return flow

Common fixes

  • Repair the wiring or replace the damaged connector
  • Replace the fuel pressure relief valve
  • Replace the pressure regulator or volume control valve
  • Replace a faulty rail pressure sensor or fuel pump if it is the cause
  • Reflash or replace the PCM only after ruling out everything else

Questions and answers

What does P009D mean?

The control module detected a high voltage in the fuel pressure relief valve control circuit. The usual culprits are wiring, a connector or the valve itself.

Can I drive with P009D?

Briefly, to get to a shop, yes. Fuel pressure may be regulated incorrectly, which can cause power loss or stalling, so don't put the repair off.

Will clearing the P009D code fix it?

Clearing it only turns off the light for a while. If the cause remains, the code will return, so check the wiring and valve first.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.