Fuel Temp Sensor #2 Open Circuit
The B1227 code is a manufacturer-specific diagnostic trouble code indicating that the control module has detected an open circuit in the fuel temperature sensor #2 circuit. This sensor, typically a negative temperature coefficient (NTC) thermistor, changes its resistance and signal voltage based on fuel temperature, allowing the PCM to adjust injection timing and fuel density calculations. An open circuit interrupts electrical continuity, causing the signal to fall outside the expected diagnostic range. This can result from internal sensor element breakage, a cut or damaged wire, or a disconnected or corroded connector. When the code sets, the module may default to a substitute temperature value, reducing fuel control accuracy.
1. Commonly Affected Makes
2. Most Common Causes
- Internal open circuit in the fuel temperature sensor #2 (damaged thermistor element)
- Cut, disconnected, or pinched wiring in the circuit between the sensor and control module
- Sensor connector with bent, corroded, or pushed-out pins causing loss of continuity
- Excessive resistance from poor splices or oxidized connection points in the harness
- Internal PCM or module failure preventing proper signal detection (rare)
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy or drivability issues due to incorrect fuel temperature compensation
4. Step-by-Step Diagnosis
Scan for codes and verify B1227 is present; check for additional related codes
Visually inspect the fuel temperature sensor #2 connector and wiring for damage, corrosion, or loose connections
Measure resistance across the sensor terminals; compare to manufacturer specifications for the given fuel temperature
Check for continuity and shorts in the wiring between the sensor and PCM using a multimeter
If wiring and sensor test OK, suspect a PCM fault; perform a PCM self-test or consult a professional
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, but with reduced fuel control accuracy. You may notice decreased fuel economy or slight drivability issues. It's best to diagnose and repair soon to avoid potential long-term effects.
How much does it cost to fix?▼
Typically $150–$400, including parts (sensor $30–$100) and labor (1–2 hours at $100–$150 per hour). Wiring repairs may add cost.