What does it mean?
This generic powertrain/engine diagnostic code can generally apply to all engines equipped with an OBD-II diesel engine (e.g., Ford, Chevy, GMC, Ram, etc.), but appears more frequently in some Mercedes Benz and VW vehicles.
Although generic, the exact repair steps may vary depending on the year, make, model, and powertrain configuration.
The “B” injection pump fuel metering control circuit is typically mounted inside/on the side of the injection pump bolted to the engine. The “B” injection pump fuel metering control circuit generally consists of a fuel rail pressure (FRP) sensor and a fuel quantity actuator.
The FRP sensor converts the amount of diesel fuel supplied by the fuel quantity plunger to the injectors into an electrical signal for the Powertrain Control Module (PCM).
The PCM receives this voltage signal to determine the amount of fuel it will deliver to the engine based on engine operating conditions. This code is set if this input does not match the normal engine operating conditions stored in the PCM’s memory, even for a second, as indicated by this diagnostic code. It also checks the FRP sensor’s voltage signal to determine if it is correct at initial key-on.
The P0260 Intermittent Injection Pump Fuel Metering Control “B” (Cam/Rotor/Injector) code may have been set due to mechanical issues (usually EVAP system mechanical problems) or electrical issues (FRP sensor circuit). These cannot be overlooked during the troubleshooting phase, especially when dealing with an intermittent issue. Refer to a vehicle-specific repair manual to determine which part is the “B” circuit for your particular application.
Troubleshooting steps may vary by manufacturer, FRP sensor type, and wire colors.
How severe is this DTC?
The severity depends on the failure. In case of mechanical failure; severe. In case of electrical failure, less severe, which the PCM can adequately compensate for.
What are some of the symptoms of the code?
Symptoms of a P0260 trouble code may include:
Malfunction Indicator Light (MIL) illumination
Decreased fuel economy
What are some common causes of the code?
Causes
of this P0260 code may include:
Open in the signal circuit to the FRP sensor – possible
Short to voltage in the signal circuit to the FRP sensor – possible
Short to ground in the FRP sensor signal circuit – possible
Open in power or ground at the FRP sensor – possible
Failed FRP sensor – probable
Failed PCM – unlikely
What are the P0260 troubleshooting steps?
A good starting point is always to check the Technical Service Bulletins (TSBs) for your vehicle. Your issue may be a known problem with a known fix issued by the manufacturer and can save you time and money during diagnosis.
Next, locate the FRP sensor on your vehicle. This sensor is typically found mounted inside/on the side of the injection pump bolted to the engine. Once located, visually inspect the connector and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Disconnect the connector and carefully inspect the terminals (the metal parts) inside the connector. See if they look burned or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic bristle brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.
If you have a scan tool, clear the diagnostic codes from memory and see if the P0260 code returns. If not, the connections were likely your problem.
If the P0260 code returns, we will need to test the FRP sensor and its associated circuits. With the key off, disconnect the electrical connector from the FRP sensor. Connect a black wire from the digital voltmeter to the ground terminal at the FRP sensor wiring harness connector. Connect the red wire from the digital voltmeter to the power terminal at the FRP sensor wiring harness connector. Turn the key to the engine-off position. Check the manufacturer’s specifications; the voltmeter should read 12 volts or 5 volts. If not, repair the power or ground wire or replace the PCM.
If the previous test passes, we will need to test the signal wire. With the connector still disconnected, move the red voltmeter wire from the power wire terminal to the signal wire terminal. The voltmeter should now read 5 volts. If not, repair the signal wire or replace the PCM.
If all previous tests have passed and you continue to get a P0260, this would most likely indicate a failing FRP sensor/fuel quantity actuator, although a faulty PCM cannot be ruled out until the FRP sensor/fuel quantity actuator has been replaced. If in doubt, seek help from a qualified automotive diagnostician. PCMs must be programmed or calibrated to the vehicle to be installed correctly.