P0656 Mercedes-Benz Code - Fuel Level Output Circuit Malfunction
Quick Answer
The Powertrain Control Module (PCM) controls the fuel gauge through the fuel gauge control circuit. Common causes include Faulty Fuel Level Gauge, Fuel Level Gauge harness is open or shorted, Fuel Level Gauge 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
- P0656 Mercedes-Benz indicates Fuel Level Output Circuit Malfunction.
- Common causes
- Common causes include Faulty Fuel Level Gauge, Fuel Level Gauge harness is open or shorted, Fuel Level Gauge 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 P0656 Mercedes-Benz Description
The PCM controls the gauge by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the controlled component. Each driver has a fault line which the PCM monitors.
What are the Possible Causes of the DTC P0656 Mercedes-Benz?
- Faulty Fuel Level Gauge
- Fuel Level Gauge harness is open or shorted
- Fuel Level Gauge circuit poor electrical connection
- Faulty Powertrain Control Module (PCM)
How to Fix the DTC P0656 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 P0656 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.
Need more information about the P0656 Mercedes-Benz code?
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Frequently Asked Questions about P0656 Mercedes-Benz Code
1. What does the OBDII code P0656 mean on a Mercedes-Benz?
P0656 indicates a "Fuel Level Output Circuit Malfunction," meaning there’s an issue with the circuit that sends the fuel level information from the fuel tank to the instrument cluster or ECM.
2. What are the common symptoms of code P0656 in a Mercedes-Benz?
Common symptoms include an inaccurate or non-functional fuel gauge, the fuel level warning light staying on, or erratic fuel level readings.
3. What causes the P0656 code to appear in a Mercedes-Benz?
The most common causes are a faulty fuel level sensor, damaged wiring or connectors in the fuel level circuit, or a malfunctioning instrument cluster.
4. Can driving with a P0656 code cause further damage to my Mercedes-Benz?
While the code itself may not cause immediate damage, relying on inaccurate fuel readings can lead to running out of fuel unexpectedly, potentially stranding you or damaging the fuel pump.
5. How do you diagnose a P0656 code in a Mercedes-Benz?
Diagnosis typically involves checking the wiring and connectors for damage, testing the fuel level sensor with a multimeter, and verifying the functionality of the instrument cluster or ECM.
6. Can a bad fuel pump trigger the P0656 code?
While uncommon, a bad fuel pump could potentially impact the fuel level sensor if they are integrated into the same assembly, leading to this code.
7. How much does it cost to fix a P0656 code on a Mercedes-Benz?
Repair costs can vary, but replacing a fuel level sensor typically costs between $200 and $600, depending on labor rates and part prices.
8. Can I reset the P0656 code without fixing the problem?
Clearing the code with a scan tool may temporarily remove it, but if the underlying issue isn’t addressed, the code will likely return.
9. Is fixing the P0656 code a DIY-friendly repair?
For experienced DIYers, replacing the fuel level sensor or inspecting wiring may be manageable, but accessing the fuel tank or circuit components can be challenging and may require professional help.
10. What tools are needed to diagnose and repair the P0656 code?
Essential tools include an OBDII scan tool, a multimeter for testing electrical circuits, and potentially a service manual for your specific Mercedes-Benz model.
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