P0255 Mercedes-Benz Code - Injection Pump Fuel Metering Control 'A' Intermittent
Quick Answer
This fault code is stored in the Engine Control Module (ECM) when the system cannot correctly control the fuel pressure. Common causes include Faulty Fuel Pump, Fuel Pump harness is open or shorted, Fuel Pump circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0255 Mercedes-Benz indicates Injection Pump Fuel Metering Control 'A' Intermittent.
- Common causes
- Common causes include Faulty Fuel Pump, Fuel Pump harness is open or shorted, Fuel Pump circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0255 Mercedes-Benz Description
Normally manufacturers will support data parameters for actual and desired fuel pressure.
A number of issues may cause this fault code to be set such as a faulty fuel rail pressure sensor, a mechanical fault with a fuel inlet metering valve could cause the valve to become stuck. An electrical fault such as an open circuit in the fuel inlet metering valve on a system with a normally closed valve will also cause this situation. A short circuit on the control wire of a normally open fuel pressure regulator will also cause this fault.
A fault in the fuel injector return system will cause the fuel pressure to be lower than expected. This causes fuel from the high-pressure circuit to be leaked back to the low-pressure circuit. A faulty maximum pressure relief valve will also cause this situation.
The high-pressure pump should also be tested to ensure it is capable of delivering the required volume of fuel.
What are the Possible Causes of the DTC P0255 Mercedes-Benz?
- Faulty Fuel Pump
- Fuel Pump harness is open or shorted
- Fuel Pump circuit poor electrical connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P0255 Mercedes-Benz?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0255 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P0255 Mercedes-Benz Code
1. What does the OBDII code P0255 mean for a Mercedes-Benz?
P0255 indicates an intermittent issue with the injection pump fuel metering control 'A', which affects the fuel delivery system's ability to regulate fuel to the engine.
2. What are the common symptoms of the P0255 code in a Mercedes-Benz?
Symptoms may include difficulty starting the engine, poor acceleration, reduced fuel efficiency, rough idling, and the illumination of the check engine light.
3. What causes the P0255 code on a Mercedes-Benz?
Possible causes include a malfunctioning injection pump, damaged fuel metering control solenoid, wiring issues, or a faulty engine control module (ECM).
4. Can I drive my Mercedes-Benz with the P0255 code active?
While it may still be drivable, driving with this code can cause performance issues and potentially lead to more severe engine damage if not addressed promptly.
5. How do you diagnose a P0255 code on a Mercedes-Benz?
Diagnosis typically involves inspecting the injection pump, checking the wiring and connectors for damage, and testing the fuel metering control solenoid for proper operation.
6. What repairs can fix the P0255 code in a Mercedes-Benz?
Repairs may include replacing the injection pump, repairing or replacing damaged wiring, cleaning or replacing the fuel metering control solenoid, or reprogramming/updating the ECM.
7. How much does it cost to repair the P0255 code on a Mercedes-Benz?
Repair costs can vary widely, but replacing an injection pump can cost between $1,000 to $2,500, while wiring repairs or solenoid replacements may be less expensive.
8. Can a dirty fuel filter cause the P0255 code on a Mercedes-Benz?
A dirty fuel filter is not a direct cause of the P0255 code but can contribute to fuel flow issues that may exacerbate the problem.
9. Does clearing the P0255 code fix the problem in a Mercedes-Benz?
Clearing the code may temporarily turn off the check engine light, but it won't resolve the underlying issue causing the code.
10. How can I prevent the P0255 code from occurring on my Mercedes-Benz?
Regular maintenance, such as replacing the fuel filter, inspecting wiring connections, and using high-quality fuel, can help prevent issues with the injection pump and fuel metering system.
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