U067D — Lost Communication With Fan 4
The vehicle bus reports loss of communication with smart cooling fan 4 (PWM brushless fan with own controller). Fan speed cannot be commanded; cooling falls back to default operation.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Cooling fan 4
- Vehicle bus wiring
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Bus wiring open or shorted
- Module without power or ground
- Module failed
Possible symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Diagnostic notes
- The malfunction indicator lamp may illuminate
- A drive cycle may be required after repair
- Reduced-power or limp mode may occur
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.