P0188
Fuel Temperature Sensor B Circuit High
Fuel & air metering
Generic OBD-II
Low
What it means
P0188 means the signal from fuel temperature sensor B is too high, which usually indicates an open circuit or a sensor reading implausibly cold. The computer uses fuel temperature to fine-tune fueling, so most vehicles keep driving normally on a default value while the fault is present. The common causes are a failed sensor or an open in its wiring.
Low
Can I keep driving? Usually drivable — the computer uses a default fuel temperature when the signal is lost — but have it fixed since the reading can affect fueling accuracy.
Common symptoms
What you'll notice
- Check-engine light on
- Often little or no change in how the car drives
- Possible small drop in fuel economy
- Minor drivability changes on some diesel applications
Common causes
Most likely first
- Faulty fuel temperature sensor B (reads high/open)Likely
- Open or high-resistance wiring in the sensor circuitCommon
- Corroded or loose sensor connectorCommon
- Damaged harness in the fuel temperature sensor circuitLess often
- Rarely, an ECM/PCM faultLess often
How to diagnose & fix
Work through it in order
- Read live data and check the fuel-temperature reading — a 'circuit high' usually reads implausibly cold, indicating an open.
- Inspect the fuel temperature sensor B connector for corrosion or a loose fit.
- Check the signal and ground wires for opens and high resistance back to the ECM.
- Measure the sensor's resistance against spec; replace it if out of range.
- Repair any wiring faults, then clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P0188?+
Generally yes. The computer substitutes a default fuel temperature, so most vehicles drive normally. It's still worth fixing because the reading fine-tunes fueling on some engines.
Can I just clear P0188?+
It returns until the sensor or wiring is repaired. Since 'circuit high' usually points to an open, focus on the connector and wiring first.
Related codes
Often seen with P0188
Read & clear P0188 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX