P0180

P0180 means the fuel temperature sensor A circuit is faulty — typically an electrical out-of-range condition, either open-circuit, shorted, or signal voltage outside the plausible window for any normal fuel temperature. Fuel temp sensor A is the primary fuel temp input (some systems have a sensor B as a redundant or downstream check, mostly on diesels and high-end FFV gasoline systems). Normal operating fuel temp window is 60-200F; the sensor is a standard NTC thermistor that reads roughly 2.5-3.0V at 100F and 0.8-1.2V at 200F, with the ECM expecting the voltage to track engine load and ambient conditions over time. Cheapest-first ladder: scan live fuel temp data with key on engine off after an overnight cold soak — the reading should match ambient air temperature within 10F (fuel and ambient air both sit at the same temperature after a long soak); if the scan tool reads -40F or +250F, the circuit is faulted. Unplug the sensor connector and observe the scan tool — a healthy ECM should bias the signal to roughly 4.8-5.0V (open-circuit reference, reading as -40F to the ECM); if it stays at the same fault reading with the sensor unplugged, the wiring is the problem. Jumper the signal wire to ground at the harness and the scan tool should read +250F+; if it doesn't, the signal wire is broken between the harness and the ECM. Expensive-misdiagnosis caveat: on systems where the fuel temp sensor is integrated into the in-tank fuel pump module, replacing the sensor means dropping the tank and swapping the entire $300-800 pump assembly — verify with an ohm-meter that the sensor element is actually failed before quoting the job.

Vehicle-specific patterns: 2004-2011 Ford F-150 FFV / Explorer FFV with the 4.6L/5.4L flex-fuel platforms throws P0180 from in-tank fuel-temp sensor corrosion after long E85 duty — the sensor is integrated into the fuel pump module and requires a full module swap on most VINs. 2005-2010 GM Impala FFV / Tahoe FFV with the 5.3L/3.5L flex-fuel commonly throws P0180 from the fuel-temp element inside the fuel pump module failing open-circuit. 2007-2012 RAM 2500/3500 6.7L Cummins throws P0180 from the rail-mounted fuel temp sensor failing after hot-soak duty cycles or from harness chafe at the fuel-rail-to-frame transition. 2003-2009 Chrysler Sebring/PT Cruiser FFV with the 2.4L/2.7L throws P0180 from harness corrosion at the tank-mounted sensor connector. Estimated repair: $150 to $850.