Fuel Temperature Sensor B Circuit Range/Performance
The P0186 code indicates that the Engine Control Module (ECM) has detected a signal from the Fuel Temperature Sensor B that is outside the expected range or that the sensor's performance is not within specifications. This sensor monitors the temperature of the fuel in the fuel rail or line, and the ECM uses this data to adjust fuel delivery and timing. A faulty sensor, wiring issues, or a poor electrical connection can cause this code.
01. Most Common Causes
- Faulty fuel temperature sensor B
- Open or shorted wiring in the sensor circuit
- Poor electrical connection at the sensor or ECM
- Contaminated fuel or debris affecting sensor operation
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation during acceleration
- Hard starting or stalling
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the P0186 code and check for any 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 from the sensor to the ECM; it should vary with fuel temperature.
Step 5: If the sensor and wiring are okay, test the ECM for proper operation or possible reprogramming.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally not recommended to drive long distances with this code, as it can cause poor engine performance and reduced fuel economy. However, you can drive short distances to a repair shop.
How much does it cost to fix?▼
The cost to fix a P0186 code typically ranges from $50 to $150, including parts and labor. The sensor itself is relatively inexpensive, but diagnostic time may add to the cost.