P0189 code meaning
Fuel Temperature Sensor B Circuit Intermittent
Powertrain system Generic code P01xx codes Check engine light
What P0189 means
Fuel temperature sensor B is an NTC thermistor: the hotter the fuel, the lower its resistance and signal voltage. On diesels it sits in the injection pump, rail or return line; on Ford gasoline direct-injection engines it is built into the rail pressure sensor, and GM uses digital rail temperature sensors on its direct-injection engines. Sensor B is the second measuring point, for example GM's 6.6 litre diesel sensor 2 or a second rail. P0189 covers jumps or brief dropouts of sensor B, the counterpart of P0184. GM documents a gradient check for sensor A (new value outside a filtered window, 10 of 15 samples); no manufacturer using P0189 was found, so the description rests on CARB and that sensor A strategy. Loose contacts and wire breaks from vibration are the typical causes.
P0189 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0189
- Check engine light on
- Jumping readings
Common causes of P0189
- Most likelyLoose contact or weak terminal tension in the connector
- Most likelyWire break or chafing from vibration
- PossibleSensor with internal dropouts
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel temperature sensor bSensor wiring
What each part of P0189 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 89 | The exact fault in that area. |
What to do next
- Note P0189 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0189
What does P0189 mean?
P0189 means "Fuel Temperature Sensor B Circuit Intermittent". Fuel temperature sensor B is an NTC thermistor: the hotter the fuel, the lower its resistance and signal voltage. It is a generic code, so it means the same on every make.
Is it safe to drive with P0189?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0189 fail an emissions test?
Yes, it can. P0189 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0189 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P0189 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.