Fuel Temperature Sensor B Circuit Range/Performance
The PCM has detected an out-of-range or inconsistent signal from the Fuel Temperature Sensor B circuit. This sensor monitors fuel temperature to adjust fuel delivery strategy, particularly in flex-fuel vehicles where accurate temperature compensation is critical for proper combustion control.
What You Might Notice
- Check Engine Light (MIL) illumination
- Possible rough idle or stumbling during acceleration
- Reduced fuel economy
- Other fuel composition-related diagnostic codes may be present
- Engine may run in limp mode on some vehicles
Most Common Causes
- 1
Defective Fuel Temperature Sensor B
The sensor itself has failed or developed an internal electrical fault, causing it to send invalid voltage signals to the PCM.
- 2
Wiring or Connector Issues
Open, shorted, corroded, or damaged wiring; loose connectors; or poor terminal connections in the sensor circuit prevent proper signal transmission.
- 3
Ambient or Intake Air Temperature Sensor Fault
A failing ambient temperature sensor or intake air temperature sensor can cause related temperature compensation errors in the fuel system calculations.
- 4
PCM Programming Error or Module Fault
Outdated PCM software or a defective PCM module may misinterpret valid sensor signals or fail to communicate with the sensor circuit correctly.
How to Diagnose It
- 1
Check Defective Fuel Temperature Sensor B — The sensor itself has failed or developed an internal electrical fault, causing it to send invalid voltage signals to the PCM.
- 2
Check Wiring or Connector Issues — Open, shorted, corroded, or damaged wiring; loose connectors; or poor terminal connections in the sensor circuit prevent proper signal transmission.
- 3
Check Ambient or Intake Air Temperature Sensor Fault — A failing ambient temperature sensor or intake air temperature sensor can cause related temperature compensation errors in the fuel system calculations.
- 4
Check PCM Programming Error or Module Fault — Outdated PCM software or a defective PCM module may misinterpret valid sensor signals or fail to communicate with the sensor circuit correctly.
How to Fix It
- 1
Replace Fuel Temperature Sensor B
Remove the defective fuel temperature sensor from the fuel tank or fuel rail and install a new sensor, ensuring proper seating and electrical connection.
- 2
Inspect and Repair Wiring and Connectors
Visually inspect the sensor circuit wiring and connectors for corrosion, damage, or loose terminals; repair or replace damaged sections and ensure all connections are secure.
- 3
Check and Replace Temperature Sensors
Test the ambient temperature sensor and intake air temperature sensor for proper operation; replace either if they are providing out-of-range signals.
- 4
PCM Software Update or Module Replacement
Contact the vehicle manufacturer or dealership to check for PCM software updates; if no update resolves the issue, the PCM module may need replacement.
Need a deeper diagnosis?
Search for related repair guides or browse by system.