U0116Lost Communication With Coolant Temperature Control Module
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- U0116 means a module no longer hears the coolant temperature control module, a separate controller for engines with electronically managed cooling. Depending on the design it may command electric pumps, map-controlled valves or fans and pass coolant status on to the engine controller. No manufacturer documents this code publicly; its companions P25AF (MIL request from that module) and U0456 (invalid data from it) are likewise known only from code lists. The basis is CARB's rule that missing communication from a digital input gets its own code, plus the general principle that electronic engine controls cut power when temperature control is uncertain. Expect a temperature or cooling warning and, as a precaution, reduced engine output.
- What you may notice
- Engine temperature or cooling system warning
- Cooling fan or electric pump running continuously
- Reduced engine power as protection
- Likely causes
- LikelyCooling module without power or ground (fuse, relay, ground point in the engine bay)
- PossibleHeat-damaged or corroded connector near the engine
- PossibleDamaged CAN or LIN wiring to the module
- RareCoolant temperature control module internally faulty
- 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 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.