Powertrain, generic · Fuel and air metering, auxiliary emission controls
P008C Fuel Cooler Pump Control Circuit/Open
Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo
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. P008C reports an open control circuit 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
Connector or wiring faulty
Fuel cooler pump faulty
Relay or fuse faulty
Output driver in the engine control module faulty
Symptoms
- Check engine light on
- Often no further symptoms
- Reduced power when fuel gets hot possible
Repair estimate
DifficultyMediumDIY possible
Parts and labour€100–400
Time0.5–2 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
fuel cooler pumpfuel cooler pump relayfuel cooler pump wiring
Related codes
References: law.cornell.edu, patents.google.com, de.wikipedia.org.