U0662 code meaning
Lost Communication With Right Rear Temperature Actuator B
What U0662 means
With four rear temperature actuators, A and B on each side, plus front units, a climate system may run many look-alike motors on LIN, where one master serves up to 15 slaves. Identical parts must be told apart, either by part variant or by position detection along a daisy chain, as the LIN article explains. That makes right rear actuator B prone to a specific trap: a new or swapped unit that was never assigned its address answers on the wrong identifier, and the master logs U0662 although the part works. No maker documents this code publicly. A genuine loss only affects the fine mixing on the right rear side; actuator A keeps basic control there. Chips such as NXP's MM908E626 show the usual three-wire hookup of supply, ground and LIN.
U0662 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0662
- Right rear temperature imprecise or slow to settle
- Code appears right after an actuator was replaced
Common causes of U0662
- PossibleReplacement or swapped actuator B without the correct LIN address
- PossibleActuator B electronics failed
- Less likelyOpen supply, ground or LIN pin at actuator B
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Rr temp actuator bVehicle bus wiring
What each part of U0662 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 62 | The exact fault in that area. |
What to do next
- Note U0662 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 U0662
What does U0662 mean?
U0662 means "Lost Communication With Right Rear Temperature Actuator B". With four rear temperature actuators, A and B on each side, plus front units, a climate system may run many look-alike motors on LIN, where one master serves up to 15 slaves. It is a generic code, so it means the same on every make.
Is it safe to drive with U0662?
U0662 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0662 fail an emissions test?
U0662 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0662 to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U0662 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.