U068F code meaning
Lost Communication With EGR Temperature Sensor C
Network system Generic code U06xx codes Check engine light
What U068F means
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.
U068F at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U068F
- Check engine light
- Low-pressure EGR reduced or disabled
Common causes of U068F
- Most likelyWiring to sensor C near the exhaust aftertreatment damaged
- PossibleConnector corroded by road splash
- PossibleSensor electronics failed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR temp sensor cVehicle bus wiring
What each part of U068F means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 8F | The exact fault in that area. |
What to do next
- Note U068F 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 U068F
What does U068F mean?
U068F means "Lost Communication With EGR Temperature Sensor C". Engines with both a high- and a low-pressure EGR loop need more temperature points, which is where slots C and D come in. It is a generic code, so it means the same on every make.
Is it safe to drive with U068F?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U068F fail an emissions test?
Yes, it can. U068F 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 U068F to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will U068F clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.