OBD-II code · Network

U0118 Lost Communication with Cabin Air Quality Sensor Module

The Cabin Air Quality Sensor Module has stopped transmitting on the vehicle data bus, so other control units no longer receive its messages. Automatic air-recirculation control loses its air-quality input. Typical causes are loss of power or ground at the module, an open or shorted CAN/LIN bus wire, a connector fault, or an internal module failure.

Is it safe to drive with U0118?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyAir quality sensor unpowered
  • PossibleCAN wiring to air quality sensor broken
  • Less likelyGateway module routing CAN messages incorrectly

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

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
0.5–2 h
Emissions test
Usually unaffected
Parts involved
Air Quality Sensor Module, Can Bus Wiring

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.