Fuel Temperature Sensor B Circuit Malfunction
The P0185 code indicates a problem in the electrical circuit of the fuel temperature sensor B, which monitors fuel temperature to optimize fuel delivery and emissions. The Powertrain Control Module (PCM) detects a voltage or resistance signal from the sensor that is outside the expected range, often due to a faulty sensor, wiring issues, or connector problems. This can lead to incorrect fuel mixture calculations, affecting engine performance and fuel economy.
01. Most Common Causes
- Faulty fuel temperature sensor B
- Open or shorted wiring in the sensor circuit
- Corroded or damaged electrical connector
- Poor electrical connection at the sensor or PCM
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Hard starting, especially in cold weather
- Poor fuel economy
- Rough idle or hesitation during acceleration
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional codes.
Step 2: Visually inspect the fuel temperature sensor B and its wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's resistance with a multimeter and compare to manufacturer specifications.
Step 4: Check the voltage signal at the sensor connector with the ignition on; should be around 5V reference.
Step 5: If sensor and wiring are okay, test the PCM for proper signal processing.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short trips, but prolonged driving may cause poor fuel economy, hard starting, and potential damage to other components. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150, including parts (sensor $20-$60) and labor (0.5-1 hour at $80-$100/hr).