P0656 code meaning
Fuel Level Output Circuit
What P0656 means
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.
P0656 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0656
- Fuel gauge reads empty, full or jumps
- Low fuel warning wrong
- Range display wrong
Common causes of P0656
- Most likelyWire or connector between module and instrument cluster open or shorted
- PossibleInstrument cluster (fuel gauge input) faulty
- Less likelyOutput driver in the module faulty
- Less likelyFuel level sender fault as root cause
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel level output circuitFuel gaugeEngine control module
What each part of P0656 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 6 | Area: computer (engine control module) and output circuits. |
| 56 | The exact fault in that area. |
What to do next
- Note P0656 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0656
What does P0656 mean?
P0656 means "Fuel Level Output Circuit". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P0656?
P0656 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P0656 fail an emissions test?
P0656 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P0656 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. This is a job for a workshop.
Will P0656 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.