Fault code P008D is called “Fuel Cooler Pump Control Circuit Low” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P008D
Fault code P008D is intended to be displayed on vehicles equipped with diesel engines. Indicates that the Powertrain Control Module (PCM) has detected a low signal level in the fuel coolant pump control circuit. Which is used to ensure normal operation of the diesel engine.
The fuel cooler pump control circuit is designed to control the operation of the fuel cooler pump. This function is specific to diesel engine vehicles and is designed to cool excess fuel. Before it is returned back to the fuel system.
The fuel is cooled by the fuel radiator, which works similarly to the engine cooling radiator, using coolant to remove heat from the fuel.
The temperature of the fuel pump is controlled by the fuel cooler pump control circuit. Which turns the pump on to run through the cooler assembly, before returning the fuel back to the fuel tank.
Code P008D is set by the PCM when a low signal is detected in the fuel cooler pump control circuit. Depending on the vehicle model, the PCM may activate other codes as well as activate the Check Engine light.
Symptoms of vehicle malfunctions
The main signal that an error P008D has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- Check engine control lamp on the control panel will light up (the code will be recorded in the memory as a malfunction).
- Unusual noises from the fuel cooler pump.
- Jerking at idle or under load.
- Decreased power of the engine.
- Increased fuel consumption.
The severity of fault P008D is high and the cause should be corrected as soon as possible. High fuel temperature is undesirable and can cause excessive wear on fuel system components. Also excessive wear of internal engine components if not corrected in time.
Factors that can cause this error code
The error code P008D can mean that one or more of the following problems have occurred:
- Defective fuel cooler pump.
- Corroded or damaged connector.
- Faulty or damaged wiring.
- Sometimes the cause is a faulty PCM module.
How to fix or reset OBD-2 code P008D
Some suggested steps for troubleshooting and fix the error code P008D:
- Read all stored data and error codes with an OBD-II scan tool.
- Clear the error codes from the computer memory.
- Test-drive the vehicle to see if fault P008D appears again.
- Visually inspect the wires and connectors going to the fuel cooler pump.
- If the error persists, check the PCM module.
Diagnose and repair of problems
The first step in the P008D troubleshooting process, is to study the technical service bulletins (TSB). In some cases, this can save a lot of time in the long run by pointing you in the right direction.
The next step is to locate all of the components associated with the fuel cooler pump control circuit. This includes the fuel cooler pump, cooler, cooler reservoir, and PCM module.
Once these components are found, a thorough visual inspection should be performed to check all associated wiring and connectors for obvious defects. Look for scuffs, scuffs, exposed wiring, or burned areas.
Signs of coolant leaks, fluid levels and condition should also be included in this process.
Circuit check
Voltage settings depend on the specific engine, fuel coolant pump control circuit configuration, and installed components. Refer to the technical data for the proper voltage range and the proper troubleshooting sequence.
Correct voltage at an inoperative fuel-coolant pump is usually a sign of an internal failure. A faulty fuel cooler pump may also produce a squeaking sound, which will progress to the point where it may produce a noise similar to a dog barking.
If this process reveals no power source or grounding, a continuity check of the wiring and connectors may be necessary to find fault P008D. Continuity tests are always performed with power disconnected from the circuit.
Normal readings should be 0 ohms of resistance unless otherwise specified in the specifications. Resistance or no continuity is an indication of faulty wiring, shorted or open connectors which must be repaired or replaced.
On which vehicles does this problem occur most frequently
Fault code P008D can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- BMW
- Chevrolet
- Dodge (RAM)
- Ford
- GMC
Fault code P008D can sometimes be found with other errors. The most common are the following: P008C, P008E.
