Fuel and air

P0258 — Injection Pump Fuel Metering Control B Circuit Low

Severity: medium Drive with care, to a shop

What P0258 means

The engine control module regulates how much fuel the injection pump delivers using an electric metering solenoid or actuator. P0258 sets when the voltage or signal in the "B" metering control circuit is lower than expected. Typical causes are an open or grounded wire, a poor connector, or a failed metering solenoid, and less often the pump itself or the ECM.

Symptoms

  • Check Engine light on
  • Rough idle or hesitation
  • Reduced power
  • Hard starting or long cranking
  • Worse fuel economy
  • Possible misfire or rough running
  • Engine may enter limp mode

Possible causes

  1. Faulty metering solenoid or actuator in the pump's B circuit
  2. Damaged or corroded wiring and connectors in the metering circuit
  3. Wiring shorted to ground
  4. Failing injection pump
  5. Faulty pump-related sensor (cam or rotor position) or injector
  6. ECM fault (rare)

How to diagnose

  1. Scan all codes and freeze-frame data, clear the code and see if it returns
  2. Inspect the pump harness and connector for chafing, oil, corrosion and loose pins
  3. Test the metering circuit for opens and shorts to ground using the factory wiring diagram
  4. Measure solenoid resistance and compare it to specification
  5. Check supply voltage and the control signal at the connector with a scan tool or scope
  6. Check fuel pressure and fuel filters
  7. Compare cylinder balance and fuel corrections, and test the injectors
  8. If wiring and solenoid are good, test the pump, and only then suspect the ECM

Common fixes

  • Repair wiring and replace damaged connectors
  • Replace the metering solenoid
  • Replace or rebuild the injection pump if the fault is internal
  • Replace a faulty sensor or injector
  • Reflash or replace the ECM if confirmed faulty

Questions and answers

What does P0258 mean?

The ECM detected a low signal in the injection pump's fuel metering control B circuit. Wiring, a connector or the metering solenoid is the usual culprit.

Can I drive with P0258?

Only briefly and carefully, to get it repaired. The engine can lose power, stall or fail to start, so don't put it off.

How do I fix P0258?

Start with the pump wiring and connector, then test the metering solenoid. Replace the pump or ECM last, after the fault is confirmed.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.