P008D Fuel Cooler Pump Control Circuit Low

On some common-rail diesels, fuel returning from the injection system is cooled in a heat exchanger connected to a low-temperature coolant circuit. An electric coolant pump, switched by the engine control module depending on fuel temperature, drives this circuit. P008D reports too low a voltage, typically a short to ground of this pump or its relay. If the pump fails for long, the fuel runs hotter; some systems then limit power to protect components.

Likely causes

Symptoms

• Check engine light on
• Often no further symptoms
• Reduced power when fuel gets hot possible

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, patents.google.com, de.wikipedia.org.