P0185: Fuel Temperature Sensor B Circuit

What does P0185 mean?

Fuel temperature sensor B is an NTC thermistor: the hotter the fuel, the lower its resistance and signal voltage. On diesels it sits in the injection pump, rail or return line; on Ford petrol direct-injection engines it is built into the rail pressure sensor, and GM uses digital rail temperature sensors on its direct-injection engines. Sensor B is the second measuring point, for example GM's 6.6 litre diesel sensor 2 or a second rail. P0185 is the general circuit fault of this sensor, the counterpart of P0180. None of the manufacturers checked uses it; GM reports sensor 2 faults as P0187/P0188. No manufacturer document using exactly this code was found; the description rests on CARB's circuit monitoring requirement and component information.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Substitute value, usually no change in driving

Common causes

• High Wire or connector open or corroded
• High Sensor faulty
• Low Control module reference or ground

Likelihood is a general estimate across vehicles; your make and model may differ.