Fuel and air

P008E — Fuel Cooler Pump Control Circuit High

Severity: medium Drive with care, to a shop

What P008E means

The engine control module runs a pump that circulates coolant through a fuel cooler, usually on diesels, to keep fuel temperature in check. P008E sets when the voltage in the pump's control circuit stays higher than expected. Typical causes are a wiring open or short to voltage, a poor connector, a failed pump, or rarely the module itself.

Symptoms

  • Check Engine Light on
  • Reduced power or surging under load
  • Higher fuel consumption
  • Noise from the fuel cooler pump
  • Hard starting when hot
  • Elevated fuel temperature

Possible causes

  1. Failed or worn fuel cooler pump
  2. Damaged, corroded or chafed wiring, or an open in the control circuit
  3. Poor connection or corrosion in the pump connector
  4. Poor ground at the pump or control module
  5. Control circuit shorted to voltage
  6. Faulty engine control module (rare)

How to diagnose

  1. Scan for codes, review freeze frame and related DTCs, then clear the code and see if it returns
  2. Inspect the pump wiring and connector for rubbing, corrosion, moisture and bent terminals
  3. Command the pump on with a scan tool bidirectional test and see if it responds
  4. Measure supply voltage and ground at the pump connector using the vehicle wiring diagram
  5. Test the control wire for opens and shorts to voltage between the module and pump
  6. Check the pump fuse and relay
  7. Test the pump itself: winding resistance, free rotation, coolant flow
  8. Suspect the module only after everything else checks out, and verify its power and grounds

Common fixes

  • Repair the wiring harness and replace damaged wires or connectors
  • Clean and restore ground connections
  • Replace the fuel cooler pump
  • Replace a bad fuse or relay
  • Reflash or replace the control module, rarely and only once confirmed

Questions and answers

Can I drive with a P008E code?

Usually yes, but only briefly and without heavy loads. Without cooling the fuel can overheat, which cuts power and can harm the fuel system, so get it diagnosed soon.

What most often causes P008E?

Wiring and connector problems are the most common: an open, corrosion or a short to voltage. The pump and a poor ground follow. A bad control module is rare.

Can I just clear the code?

You can, but it will come back if the cause remains. Find the circuit or pump fault 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.