U068FLost Communication With EGR Temperature Sensor C
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Engines with both a high- and a low-pressure EGR loop need more temperature points, which is where slots C and D come in. U068F means the controller lost the digital messages of EGR temperature sensor C. There is no public manufacturer documentation for it. In GM's 2025 diesel table 25OBDG04B, sensor C is an air temperature point upstream in the low-pressure EGR path, read as a resistance: below 7 ohms it gives P04D0 after 30 of 38 counts, Type A, and after more than 8 hours off it may not stray over 20 °C from the mean of intake air and fuel temperature at key-on (P04CF). A SENT version with its own lost-communication check is not listed there. CARB requires separate detection when a digital input is silent. Analog faults are P04CE to P04D2. Low-pressure EGR is then usually reduced or switched off.
- What you may notice
- Check engine light
- Low-pressure EGR reduced or disabled
- Likely causes
- LikelyWiring to sensor C near the exhaust aftertreatment damaged
- PossibleConnector corroded by road splash
- PossibleSensor electronics failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.