P0258: Injection Pump Fuel Metering Control B Low (Cam/Rotor/Injector)
May cause rough idle, loss of power, hard starting, and increased fuel consumption; check engine light illuminated
Overview
P0258 indicates a low voltage or signal condition in the fuel injection pump’s ‘B’ metering control circuit, often due to electrical faults, wiring issues, sensor/output malfunctions, or component failures
Common Symptoms
- Check Engine Light illuminated
- Rough idle or engine hesitation
- Reduced engine power/performance
- Hard starting or longer crank time
- Decreased fuel economy
Most Common Causes
Low voltage signal to PCM from injection pump fuel metering control B triggers the code
Electrical resistance or breaks can reduce signal voltage below threshold
Incorrect sensor input can mimic low signal condition
Rare, but possible if all wiring and component tests pass
Diagnostic Steps
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Use a professional OBD‑II scanner to confirm P0258 and record freeze frame dataExpected: P0258 stored with associated data such as engine load and voltage valuesInterpretation: Confirms persistent fault and data context
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Perform visual inspection of wiring and connectors to injection pump fuel metering control B circuitExpected: No corrosion, breaks, or loose pin connectionsInterpretation: If damaged, repair wiring/connectors
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Test circuit voltage and continuity with a multimeterExpected: Voltage within specified OEM range; continuity without high resistanceInterpretation: Low voltage or open circuit indicates wiring/component issue
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Test fuel injection pump metering control solenoid/actuator and related sensorsExpected: Proper resistance and signal waveform per manufacturer specInterpretation: Out‑of‑spec values suggest component replacement
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Check ECM/PCM for faults and perform software update if TSB applicableExpected: No internal ECM errors; latest software calibrationInterpretation: ECM issue possible if wiring and components are verified good
Repair Solutions
Cost depends on extent of wiring harness damage and labor
Expensive component; confirm failure before replacement
Requires professional programming and verification
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Mistaking P0258 for simple injector flow fault or generic engine misfire without confirming injection pump signal circuit
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