U067C code meaning
Lost Communication With Fan 3
Network system Generic code U06xx codes Check engine light
What U067C means
Some engines need a third electric cooling fan, for instance for a charge-air or auxiliary radiator, and LIN lets each fan carry its own speed electronics. GM's 2025 diesel table 25OBDG04B uses U067C for cooling fan 3: the response frame CFM3_Rsp must be missing for at least 2,437.5 ms, the LIN channel enabled and battery voltage above 11 V; the code is Type B, so the MIL lights after two trips. While it is active GM suspends the fan 3 speed checks, P2CBB for running slower than modelled and P30F2/P30F3 for feedback out of range, the high limit being 4,000 rpm. On the engines of GM's 23OBDG07 and 24OBDG07 the same fan instead sets the GM-specific U112A on a third LIN line. Watch engine temperature under load.
U067C at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U067C
- Check engine light after two trips
- High coolant or charge-air temperature at low speed or when towing
- Fan 3 silent or running constantly
Common causes of U067C
- Most likelyLIN wire to fan 3 chafed or open
- PossibleHigh-current supply, fuse or ground of fan 3 faulty
- PossibleFan 3 controller electronics failed
- Less likelyFan connector corroded by road spray
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cooling fan 3Vehicle bus wiring
What each part of U067C means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 7C | The exact fault in that area. |
What to do next
- Note U067C 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 U067C
What does U067C mean?
U067C means "Lost Communication With Fan 3". Some engines need a third electric cooling fan, for instance for a charge-air or auxiliary radiator, and LIN lets each fan carry its own speed electronics. It is a generic code, so it means the same on every make.
Is it safe to drive with U067C?
Drive gently and only to a workshop. With U067C the car can go into limp mode (reduced power) to protect itself.
Will U067C fail an emissions test?
Yes, it can. U067C 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 U067C to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U067C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.