P0656: The engine computer found a fault in the fuel level output circuit that feeds the fuel gauge signal
Fuel level output circuit malfunction
Severity: Severity not verified — if the car runs badly, have it inspected
The sources define the code and say it should not affect how the engine runs, but give no formal urgency rating, so urgency is not verified. A wrong fuel gauge can leave you short of fuel.
P0656 in short
P0656 means the engine computer found a fault in the fuel level output circuit, the signal it sends out for the fuel gauge. TroubleCodes.net lists wiring and the computer as probable causes and says it should not affect how the car runs. Do not trust the fuel gauge until it is checked.
This code is about the fuel level signal the computer outputs, not about fuel delivery to the engine.
TroubleCodes.net lists wiring and the engine control module as probable causes, and its editor says the code should not change how the vehicle runs. The same editor suggests the fuel level sensor in the tank, the path to the instrument cluster, or cluster-to-computer communication as places to look.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Open or shorted wiring in the fuel level signal circuit
Common general cause- Why it ranks here
- TroubleCodes.net lists wiring first.
- What would change this
- Rises if a visual and electrical check finds a fault here. Falls if it checks out.
Cause 2: Fuel level sensor in the tank or the signal path to the cluster
Common general cause- Why it ranks here
- The site's editor points to the tank sensor and the signal path to the cluster as things to check.
- What would change this
- Rises if a visual and electrical check finds a fault here. Falls if it checks out.
Cause 3: Engine computer output fault
Common general cause- Why it ranks here
- Named by TroubleCodes.net; ranked last because wiring and sensor faults are more common.
- What would change this
- Rises if a visual and electrical check finds a fault here. Falls if it checks out.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Compare the fuel gauge reading with how much fuel you know is in the tank.
IfGauge reads wrong or jumps
It meansFuel level signal is faulty.
IfGauge reads correctly
It meansFault may be intermittent; have the circuit checked.
Step 2: Have a shop check the fuel level sensor, its wiring and the cluster signal path.
Warning:The fuel level sensor sits in the fuel tank; opening it releases fuel vapour, so a shop should do it with no sparks or open flame.
IfSensor or wiring is faulty
It meansRepair that part.
Points to: Fuel level sensor in the tank or the signal path to the cluster
IfWiring is good
It meansComputer or cluster signal fault is suspect.
Symptoms
- Check engine light on with the code stored
- Fuel gauge that reads wrong, jumps or sticks
How to fix
Step 1: Note the fuel gauge reading against the fuel you actually have, and refuel on trip distance rather than the gauge until it is checked.
Parts and cost context
- Fuel level sensor (sending unit):Sits in the tank; a shop usually drops the tank or opens an access panel to reach it. Labour varies; get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
We don't have reviewed vehicle-specific evidence for P0656 yet. The causes and tests above apply across vehicles.
Related codes
No curated relationships for P0656 yet.
P0656 questions
Will P0656 affect how the car runs?
TroubleCodes.net says it should not affect how the vehicle runs. The risk is a wrong fuel gauge.
Sources and review
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error