P0255 - Injection Pump Fuel Metering Control A Intermittent
The P0255 code indicates an intermittent fault in the fuel metering control circuit 'A' of the injection pump, which may involve the cam, rotor, or injector components. This typically points to an electrical or mechanical issue within the pump's fuel metering solenoid or actuator, causing erratic fuel delivery. The ECM detects an unexpected voltage or signal from the metering control circuit, often due to wiring problems, connector corrosion, or internal pump wear.
1. Most Common Causes
- Faulty injection pump fuel metering solenoid
- Open or shorted wiring in the metering control circuit
- Corroded or loose electrical connectors at the pump
- Internal mechanical wear in the injection pump (cam/rotor)
- Failed ECM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine hard to start or no start
- Rough idle or engine misfire
- Loss of power under acceleration
- Poor fuel economy
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Visually inspect wiring and connectors at the injection pump for damage, corrosion, or looseness.
Step 3: Test the fuel metering solenoid resistance and compare to manufacturer specs.
Step 4: Check for 12V power and ground at the solenoid connector with key on.
Step 5: If wiring and solenoid are okay, suspect internal pump failure and perform a pump flow test.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The intermittent metering control can cause sudden power loss or stalling, posing a safety risk.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Repair costs vary widely: wiring repairs may be under $200, while injection pump replacement can exceed $1,500.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.