U0689 code meaning
Lost Communication With Turbocharger/Supercharger B Temperature Sensor
Network system Generic code U06xx codes Check engine light
What U0689 means
Twin-charger engines may monitor a temperature at the second charger, for instance to protect the compressor or turbine of charger B from overheating; CARB's diesel data list includes compressor inlet as well as turbine inlet and outlet temperatures. U0689 means the reading of the temperature sensor for charger B arrives over a digital link and that link has failed. Such a channel can be built into a combined pressure sensor, as Infineon's KP276 shows with its SENT-transmitted NTC input. No manufacturer documents U0689 publicly, and none of the Ford or GM summaries examined contains it. Circuit faults of an analog sensor are P2B8F to P2B92, charger A's link loss is U0643. With the value gone, the controller may protect the charger by limiting boost.
U0689 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0689
- Check engine light
- Boost reduced as a precaution
- Otherwise often unchanged driving
Common causes of U0689
- Most likelyWiring near charger B damaged by heat
- PossibleConnector loose or corroded
- PossibleTemperature sensor or its interface electronics failed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Turbo b temp sensorVehicle bus wiring
What each part of U0689 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 89 | The exact fault in that area. |
What to do next
- Note U0689 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 U0689
What does U0689 mean?
U0689 means "Lost Communication With Turbocharger/Supercharger B Temperature Sensor". Twin-charger engines may monitor a temperature at the second charger, for instance to protect the compressor or turbine of charger B from overheating; CARB's diesel data list includes compressor inlet as well as turbine inlet and outlet temperatures. It is a generic code, so it means the same on every make.
Is it safe to drive with U0689?
Drive gently and only to a workshop. With U0689 the car can go into limp mode (reduced power) to protect itself.
Will U0689 fail an emissions test?
Yes, it can. U0689 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 U0689 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. This is a job for a workshop.
Will U0689 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.