P0259
UniversalP0259 indicates that the powertrain control module (PCM) has detected a high circuit condition in the 'B' fuel injection pump fuel metering control circuit, which regulates the amount of fuel delivered to the engine via the camshaft, rotor, or injector.
High SeverityThis code means the vehicle's computer has detected an electrical problem, specifically a high voltage signal, in the fuel metering control circuit 'B' of the injection pump. This often leads to issues with the engine's fuel delivery, resulting in poor performance or a no-start condition.
⚠️ Before You Begin (Safety First)
Always wear appropriate personal protective equipment, including safety glasses and gloves. Disconnect the battery before working on electrical components. Exercise extreme caution when working with the fuel system due to high pressures and flammable fuel. Allow the engine to cool down before attempting repairs to avoid burns.
Common Symptoms
- Check Engine Light illuminated
- Reduced engine power or acceleration
- Rough idling
- Engine stalling or misfires
- Difficulty starting the engine
- Poor fuel economy
Common Causes
- Faulty fuel metering control valve (actuator)
- Open or short circuit in the fuel metering control circuit wiring
- Corroded or loose electrical connectors
- Faulty Powertrain Control Module (PCM) (rare)
- Problems with the fuel injection pump itself
Frequently reported on: General/Universal
Diagnostic Steps
- Visually inspect the wiring and connectors for the fuel metering control valve and injection pump for damage, corrosion, or loose connections.
- Check for any obvious fuel leaks around the injection pump or fuel lines.
- Using a multimeter, test for continuity and proper voltage at the fuel metering control valve connector (refer to service manual for specific values).
- If accessible, try to test the resistance of the fuel metering control valve itself (again, consult service manual).
- Clear the code and retest to see if it returns, as it might be an intermittent issue.
👨🔧 When to Call a Professional
If basic diagnostic steps do not resolve the issue, or if you are uncomfortable testing high-pressure fuel systems or complex electrical circuits, it is highly recommended to consult a certified mechanic. Specialized tools and diagnostic equipment are often needed to accurately pinpoint the fault without causing further damage.
Commonly Asked Questions
What is a fuel metering control valve?
It's an electronic valve on the fuel injection pump that precisely regulates the amount of fuel delivered to the injectors, crucial for engine performance and efficiency.
Can I drive with a P0259 code?
It is not recommended to drive with this code. It can lead to severe engine performance issues, potential stalling, and could cause further damage to the fuel system or engine if not addressed.
Is the fuel injection pump always the problem?
Not necessarily. While the code relates to the injection pump's metering control, the issue could be with the wiring, electrical connectors, or even the engine's computer, although a faulty metering control valve is a common culprit.
How do I test the fuel metering control valve?
You'll typically need a multimeter to test for proper resistance and voltage at the valve's electrical connector. A service manual for your specific vehicle is crucial for finding the correct values and testing procedures.
What does 'High' mean in the code definition?
'High' usually refers to a voltage condition, indicating that the PCM is detecting a higher-than-expected voltage or an open circuit within the 'B' fuel metering control circuit.