P0258
Injection Pump Fuel Metering Control B Low
If your vehicle's onboard computer has flagged the diagnostic trouble code P0258, it refers to a detected anomaly regarding "Injection Pump Fuel Metering Control B Low". This systemic engine fault needs a targeted check before symptoms expand.
Driver's Summary
When your OBD2 scanner shows P0258, the engine control module has flagged an issue specifically related to injection pump fuel metering control b low. The most common signs are engine won't start, severely reduced power. Given the high severity of this code, continuing to drive risks significant mechanical damage. Have it diagnosed immediately.
Symptoms
Engine won't start, severely reduced power
Common Causes
- Short to ground in control B circuit
- Failed metering valve
- Failed fuel pump driver module
- Damaged harness
How to Fix
- 1 Repair short to ground
- 2 Replace metering valve
- 3 Replace fuel pump driver module
- 4 Repair harness
Technical Explanation
P0258 is stored after the control module confirms the fault over multiple ignition cycles, ruling out transient electrical noise as the cause. For injector-specific codes, the ECM monitors the injector control circuit voltage drop during each pulse; a shorted or open injector presents a characteristic resistance signature that differs measurably from a healthy unit. After two failed drive cycles, the code transitions from a pending to a confirmed DTC, and the PCM activates the MIL. Clearing the code without repairing the fault will result in re-illumination within one to two complete drive cycles.
Is It Safe to Drive?
This fault carries real mechanical risk. The root causes — including short to ground in control b circuit — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
Mechanic's Pro Tip
Module replacement should always be the last resort for P0258 after exhaustively verifying all power supply circuits, ground connections, and communication bus wiring. Use a wiring diagram to locate all fuses, relays, and ground points for the affected module, and measure voltage drop on each ground with the circuit loaded. A module "failure" is frequently a corroded ground eyelet or a weak battery causing brownout conditions — fix these first and you'll save hundreds of dollars on an unnecessary module replacement.
Metering valve: 200 - 500