P0188 Code: Fuel Temperature Sensor B Circuit High
🟢 Low severity · drivable
Yes, the engine will usually run fine, but cold starts and fuel economy may be off — get it checked soon.
What P0188 means
The fuel temperature sensor tells the computer how warm the fuel is so it can adjust fuel pressure and injection timing. This code means the sensor B circuit is sending a voltage higher than the computer expects. It usually points to a failed sensor or a wiring problem.
Symptoms
- Check engine light on
- Hard starting in cold weather (diesel)
- Slightly worse fuel economy
- Engine may run rough
Common causes
- most common: Faulty fuel temperature sensor B
- common: Shorted or damaged wiring in the sensor circuit
- common: Corroded or loose connector pins
- rare: Engine computer (PCM) fault
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the fuel temperature sensor B | Yes | $40–120 |
| Inspect and repair the sensor wiring or connector | Yes | $20–80 |
Frequently asked questions
Can I drive with a P0188 code?
Yes. The car will usually run, but you may notice harder cold starts and slightly worse fuel economy. Get it checked soon.
What does the fuel temperature sensor do?
It measures fuel temperature so the computer can fine-tune fuel pressure and injection timing, especially on diesel engines.
How much does it cost to fix a P0188?
The sensor itself is usually $40–120. A wiring repair is usually cheaper, around $20–80.
Related codes
P0187
P0187 Code: Fuel Temperature Sensor B Circuit Low
P0189P0189 Code: Fuel Temperature Sensor B Circuit Intermittent
P0185P0185 Code: Fuel Temperature Sensor B Circuit Malfunction
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.