Drive with caution — fix soon.
This code means the engine computer has detected a problem with the fuel composition sensor circuit, the sensor that measures the ethanol content of your fuel in flex-fuel vehicles. It's usually caused by a failed sensor, wiring or connector problems, or contamination. It's generally a sensor-level issue and is fixable without major engine work once the wiring and sensor are checked.
$120 – $500
Varies by vehicle and root cause.
Usually yes. The engine can typically still run, but the fuel mixture may be slightly off, so it's best to have it diagnosed within a week or two to avoid rough running or wasted fuel.
A wiring or connector repair may be around $120, while replacing the fuel composition sensor itself, including parts and labor, can run up to about $500.
It's moderate. It rarely leaves you stranded, but a wrong fuel reading can cause drivability problems and reduced economy, so it's worth fixing before it gets worse.
In flex-fuel vehicles, this sensor measures how much ethanol is in the fuel so the computer can adjust the air-fuel mixture and timing. A P0176 means the sensor circuit isn't reporting properly.