Fix P0258: STEP-BY-STEP diagnostic GUIDE!

The P0258: Injection Pump Fuel Metering Control B Low (Cam/Rotor/Injector) code indicates that there is a low voltage issue in the fuel metering control system for the injection pump, specifically related to Control B. This system is crucial for regulating the amount of fuel injected into the engine, and a low voltage condition can lead to improper fuel delivery, affecting engine performance. This issue could stem from a faulty injection pump, wiring problems, or a malfunctioning Powertrain Control Module (PCM).

P0258 – Quick Overview

Meaning	P0258: Injection Pump Fuel Metering Control B Low (Cam/Rotor/Injector)
Is it serious?	Yes, this code can be serious as low voltage in the circuit may cause improper fuel delivery, leading to poor engine performance, stalling, or even engine damage if not addressed.
Possible causes	– Low voltage in the injection pump fuel metering control B circuit – Faulty injection pump fuel metering control B – Wiring or connector issues – Faulty PCM
How to diagnose?	– Measure the voltage in the injection pump fuel metering control B circuit. – Inspect the sensor for proper operation. – Check wiring and connectors for defects. – Replace or repair any faulty components.

P0258 Meaning

The P0258: Injection Pump Fuel Metering Control B Low (Cam/Rotor/Injector) code indicates that the voltage in the circuit for the injection pump fuel metering control B is lower than it should be. This condition can result in improper control of the fuel metering, leading to issues such as rough idling, poor fuel efficiency, or even engine stalling. The low voltage could be due to a problem with the control itself, wiring issues, or a malfunctioning PCM.

Step-by-step diagnostic guide

Follow the outlined procedure to diagnose this DTC by eliminating possible causes one by one.

Action	Description	Tools Needed
Check for Other Codes	Use an OBD-II scanner to check if there are any other related codes present. These might give additional clues about the problem.	OBD-II Scanner
Measure Voltage in the Circuit	Use a multimeter to measure the voltage in the injection pump fuel metering control B circuit. Compare the readings to the manufacturer’s specifications to determine if the voltage is too low.	Multimeter, Manufacturer’s Specifications
Inspect the Sensor	Visually inspect the sensor associated with the injection pump fuel metering control B for any signs of damage, corrosion, or disconnection. Ensure it is securely attached and functioning properly.	Flashlight, Safety Gloves
Inspect Wiring and Connectors	Carefully check the wiring and connectors leading to the injection pump fuel metering control B for any signs of wear, corrosion, or breaks. Look for loose or disconnected wires that could cause low voltage.	Flashlight, Multimeter
Repair or Replace Damaged Wiring/Connectors	If any wiring or connectors are damaged, shorted, or corroded, repair or replace them. Ensure all connections are secure and free from contaminants.	Wire Strippers, Electrical Tape, Replacement Wires/Connectors
Check the PCM (Powertrain Control Module)	Inspect the PCM and its connections for any signs of damage or loose connections. If the PCM is suspected to be faulty and causing low voltage, it may need reprogramming or replacement.	OBD-II Scanner, Multimeter
Clear the Code and Test Drive	After completing the necessary repairs, clear the P0258 code using the OBD-II scanner. Take the vehicle for a test drive to ensure the issue is resolved and the code does not return.	OBD-II Scanner, Vehicle Owner’s Manual
Recheck for Codes	After the test drive, re-scan the vehicle to ensure the P0258 code has not reappeared. If the code returns, further diagnosis may be required.	OBD-II Scanner