U067DLost Communication With Fan 4
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U067D is meant for a fourth cooling fan with its own network interface that has stopped answering. Four electrically commanded fans are rare. No manufacturer documents U067D publicly: GM's 2025 diesel table 25OBDG04B ends at fan 3, and the engines in GM's 23OBDG07 and 24OBDG07, which do have a fourth LIN fan, report it with the GM-specific code U112B once its response frame ECM_LIN3_CFM4_RSP has been missed three times, maturing over two trips. LIN suits such small motor nodes, and cooling fan motors are a classic application. If fan 4 is wired conventionally, its faults appear as P2C3E to P2C40 for the control circuit and P2C42 for performance. Losing one of four fans mostly shows when cooling demand is high.
- What you may notice
- Temperature climbs in traffic or under heavy load
- Warning light depending on manufacturer
- Fan 4 does not run
- Likely causes
- LikelyBus wire to fan 4 damaged
- PossibleFan 4 power feed or ground interrupted
- PossibleFan 4 electronics or motor failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.