P0255
Injection Pump Fuel Metering Control A Intermittent
The appearance of the standard OBD2 trouble fault code P0255 is an indicator that your vehicle ECU triggered a threshold alert for "Injection Pump Fuel Metering Control A Intermittent". Understanding the root component breakdown helps avoid expensive diagnostic fees.
Driver's Summary
Your vehicle's computer logged P0255 after detecting a malfunction in the injection pump fuel metering control a intermittent system. Typical symptoms include intermittent stalling, check engine light flashes. While the car is usually drivable, you should schedule a diagnosis within the next few days to prevent the issue from worsening.
Symptoms
Intermittent stalling, check engine light flashes
Common Causes
- Loose connection at the injection pump
- Wiring harness chafing
- Failing metering valve
- Air bubbles in fuel system
How to Fix
- 1 Secure and clean connector
- 2 Repair chafed wiring
- 3 Replace metering valve
- 4 Bleed fuel system
Technical Explanation
Code P0255 is confirmed when the ECM's diagnostic algorithm detects a parameter deviation that persists across a defined number of consecutive drive cycles. 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. The MIL illuminates after the fault is confirmed on two consecutive drive cycles, and the freeze frame data captured at first detection is stored in the PCM's memory for diagnostic reference.
Is It Safe to Drive?
You can drive short distances, but the symptoms — intermittent stalling, check engine light flashes — indicate the affected system is compromised. Leaving this unresolved will lead to progressively worse fuel economy and potential damage to components beyond the original fault.
Mechanic's Pro Tip
Before replacing any component on P0255, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Connector repair: 50; Metering valve: 200 - 500