Fuel Temperature Sensor B Circuit Intermittent
The P0189 code indicates that the Engine Control Module (ECM) has detected an intermittent signal from the fuel temperature sensor B circuit. This sensor monitors the temperature of the fuel in the fuel rail or tank, and the ECM uses this data to adjust fuel delivery and timing. An intermittent fault means the signal is erratic or drops out sporadically, often due to wiring issues, poor connections, or a failing sensor. This can lead to incorrect fuel mixture calculations, affecting engine performance and fuel economy.
01. Most Common Causes
- Faulty fuel temperature sensor B
- Damaged or corroded wiring/connectors in the sensor circuit
- Intermittent short or open in the circuit
- Poor electrical connection at the sensor or ECM
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or hesitation
- Poor fuel economy
- Hard starting or stalling
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other related 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 and compare to manufacturer specifications; replace if out of range.
Step 4: Check for intermittent shorts or opens by wiggling the wiring harness while monitoring the sensor signal with a multimeter or scan tool.
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, if the symptoms are mild, you may drive to a repair shop.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150, including parts and labor. The sensor itself is usually inexpensive, but diagnostic time may add to the cost.