Injection Pump Fuel Metering Control B Range/Performance
Code P0257 indicates that the Engine Control Module (ECM) has detected a range or performance problem in the fuel metering control circuit 'B' of the injection pump. This typically involves the fuel metering solenoid or actuator that regulates fuel delivery based on engine demand. The ECM monitors the feedback signal from the metering control and compares it to the desired value; if the actual position or response is out of expected range, this code sets. Common causes include a faulty fuel metering actuator, wiring issues, or internal pump failure.
1. Most Common Causes
- Faulty fuel metering actuator/solenoid
- Wiring or connector issues in the metering control circuit
- Internal injection pump failure
- ECM software or hardware malfunction
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine hard to start or no start
- Poor engine performance, hesitation, or stalling
- Reduced fuel economy
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect wiring and connectors to the injection pump metering control.
Step 3: Test the fuel metering actuator resistance and voltage supply per manufacturer specs.
Step 4: Perform a bidirectional test of the actuator using a scan tool if available.
Step 5: If all else passes, suspect internal pump failure and consider replacement.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The vehicle may experience stalling or loss of power, which can be dangerous. Have it diagnosed promptly.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Repair costs vary widely: a new injection pump can be $1,000-$3,000, while wiring repairs may be under $200.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.