U0116 code meaning
Lost Communication With Coolant Temperature Control Module
Network system Generic code U01xx codes Check engine light
What U0116 means
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.
U0116 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0116
- Engine temperature or cooling system warning
- Cooling fan or electric pump running continuously
- Reduced engine power as protection
Common causes of U0116
- Most 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
- Less likelyCoolant temperature control module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Coolant temperature moduleCAN bus wiring
What each part of U0116 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 16 | The exact fault in that area. |
What to do next
- Note U0116 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 U0116
What does U0116 mean?
U0116 means "Lost Communication With Coolant Temperature Control Module". U0116 means a module no longer hears the coolant temperature control module, a separate controller for engines with electronically managed cooling. It is a generic code, so it means the same on every make.
Is it safe to drive with U0116?
Drive gently and only to a workshop. With U0116 the car can go into limp mode (reduced power) to protect itself.
Will U0116 fail an emissions test?
Yes, it can. U0116 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 U0116 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U0116 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.