P0258 code definition
Injection Pump Fuel Metering Control “B” Low (Cam/Rotor/Injector)
What the P0258 code means
P0258 is an OBD-II generic code for the injection pump fuel metering control valve circuit having low or no current flow when the engine control module (ECM) does not receive a signal from the fuel enrichment valve.
What causes the P0258 code?
The engine control module (ECM) monitors the fuel injection pump metering valve position current feedback when commands to control the valve are sent to the valve from the ECM.
The ECM attempts to move the valve, and if the current is low or out of specifications, then it sets the code P0258 and turns on the Check Engine Light.
The problem can be due to an open circuit in the wiring or connector to the injection pump.
The battery is below 8 volts or the injector power relay has an open circuit.
What are the symptoms of the P0258 code?
- The Check Engine Light will be illuminated and the code is set in ECM memory as a fault.
- The engine may run too lean or too rich depending on the fuel valve failed position.
- The engine may have reduced engine power and rough running conditions.
How does a mechanic diagnose the P0258 code?
Scans codes and documents the code in the ECM
Diagnose code as per the manufacturer's pinpoint test to verify the pump voltage supply and circuits are good to prevent replacing a good injection pump
Tests the battery to make sure it does not fall below 8 volts during cranking or vehicle operation
Verifies voltage is above 8 volts getting to the fuel injection pump fuel control circuit
Common mistakes when diagnosing the P0258 code?
Clearing ECM memory codes before checking the freeze frame data of the failure
Failing to clear ECM codes after the P0258 codes are fixed and then retesting the system
Failing to make sure the batteries are fully charged and above 8 volts during the starting of the engine
How serious is the P0258 code?
Code P0258 is an indication that the fuel injection pump cannot control fuel into the engine and the power supply to the injection pump must be repaired or the pump must be replaced to fix the code and drive symptoms.
What repairs can fix the P0258 code?
- Replace the fuel injection pump
- Clear codes and road tests the vehicle to verify the code does not return
- Replaces the fuel filter and contaminated fuel before the injection pump is replaced
- Repairs or replaces the battery power supply to the injection pump circuit
Additional comments for consideration regarding the P0258 code
Code P0258 is generated by a diesel engine vehicle that has an injection pump that cannot control the amount of fuel injected into the cylinders and will cause the code to set. Some vehicles may have a fuel valve that can be replaced without replacing the entire fuel injection pump. Follow the manufacturer pinpoint tests for diagnosis and repair for your vehicle. The vehicle batteries cannot fall below 8 volts to supply enough voltage to the fuel injection pump fuel control valve, and if it falls below the 8 volts, it can generate the failure code. Check the batteries first.
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