P0656Fuel Level Output Circuit
- Generic OBD-II code · Powertrain
- How the car detects it
- The engine module switches this hard-wired output with its own driver and checks the circuit electrically (open, short to ground or voltage) – it cannot see whether the lamp lights; on CAN-based cars such faults appear as U codes. Where the engine module reads the fuel level sender itself – it needs the level for the evaporative leak test – it passes the level on to the fuel gauge. GM Europe's 2010 Saab 9-5 reads two senders (0.5–3.5 V), calculates the level in percent and sends it over CAN via the body module to the instrument cluster; there a failure would be a U code. P0656 reports a fault on a hard-wired level output. No manufacturer document available to us uses this code; the description follows CARB and the component. The gauge then reads empty, full or jumps and the low fuel warning is wrong; engine and evaporative test are not affected. Sender input faults are P0460–P0464.
- What you may notice
- Fuel gauge reads empty, full or jumps
- Low fuel warning wrong
- Range display wrong
- Likely causes
- LikelyWire or connector between module and instrument cluster open or shorted
- PossibleInstrument cluster (fuel gauge input) faulty
- RareOutput driver in the module faulty
- RareFuel level sender fault as root cause
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.