P0185
UniversalFuel Temperature Sensor B Circuit Malfunction
Medium SeverityThis code indicates an issue with the electrical circuit of the Fuel Temperature Sensor B, which monitors the temperature of the fuel in the tank or fuel line. A malfunction in this circuit can lead to incorrect fuel mixture calculations, potentially affecting fuel economy and engine performance.
⚠️ Before You Begin (Safety First)
Always ensure the engine is off and cool before working on any fuel system components. Disconnect the battery's negative terminal to prevent electrical shocks or accidental system activation. Be aware of fuel pressure and potential spills; wear appropriate eye protection and gloves.
Common Symptoms
- Check Engine Light illuminated
- Reduced fuel economy
- Engine performance issues (rough idle, hesitation)
- Difficulty starting (less common, but possible)
- Failed emissions test
Common Causes
- Faulty Fuel Temperature Sensor B
- Damaged or corroded wiring or connectors in the sensor circuit
- Short to voltage or ground in the sensor circuit
- Open circuit in the sensor wiring
- Faulty Powertrain Control Module (PCM) (rare)
Frequently reported on: General/Universal
Diagnostic Steps
- Visually inspect the Fuel Temperature Sensor B and its wiring harness for any obvious damage, corrosion, or loose connections.
- Locate the sensor (often on the fuel rail, fuel tank, or in the fuel line, depending on the vehicle).
- Using a multimeter, test the sensor's resistance and voltage according to the vehicle's service manual specifications.
- If the sensor is faulty, carefully disconnect the electrical connector and remove the sensor, replacing it with a new, OEM-specified part.
- Clear the P0185 code from the PCM using an OBD-II scanner and test drive the vehicle to confirm the repair.
👨🔧 When to Call a Professional
If diagnostic steps reveal complex wiring issues, or if the problem persists after replacing the sensor, it's best to consult a certified mechanic to diagnose potential PCM issues or underlying electrical problems.
Commonly Asked Questions
What does Fuel Temperature Sensor B do?
It measures the temperature of the fuel, providing data to the engine's computer (PCM) to optimize fuel delivery and ensure efficient combustion.
Can I drive with a P0185 code?
While you might be able to drive, it's not recommended for long periods as it can lead to decreased fuel efficiency and potential engine performance issues.
Where is Fuel Temperature Sensor B typically located?
Its location varies by vehicle, but it can often be found on the fuel rail, within the fuel tank sending unit, or inline in the fuel delivery system. Consult your vehicle's service manual.
Is P0185 related to a bad fuel pump?
Not directly. P0185 indicates an issue with the fuel temperature sensor's circuit, not necessarily the fuel pump itself, though both are part of the fuel system.
How much does it cost to fix P0185?
The cost can vary, but replacing the fuel temperature sensor itself typically ranges from $50 to $200 for parts, plus labor if done by a professional.