U0653 code meaning
Lost Communication With EGR Sensor C
Network system Generic code U06xx codes Check engine light
What U0653 means
On GM's 2025 diesel with high- and low-pressure EGR (table 25OBDG04B), EGR sensor C is the SENT position sensor of the low-pressure valve, which as usual for such loops takes exhaust after the particulate filter and feeds it ahead of the compressor. Oddly, the table's text calls this valve the B position sensor while filing its codes under C. U0653 is stored when 480 of 600 checks every 6.25 ms see outdated data while the protocol sits permanently low or high, a corrupt message, or counters that froze; GM rates this Type A, lighting the MIL on the first trip. A raw level below 1 % on the same sensor is P044C, and P044A to P044E cover the analog faults of sensor C. While the low-pressure valve position is unknown, its loop is shut and the high-pressure loop has to cover alone.
U0653 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0653
- MIL on from the first trip
- Low-pressure EGR disabled, higher NOx
- EGR monitor not ready
Common causes of U0653
- Most likelyWiring to the low-pressure EGR valve damaged near the exhaust
- PossibleConnector corroded by road splash
- PossiblePosition sensor in the low-pressure EGR valve failed
- Less likelyEngine controller input fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR sensor cVehicle bus wiring
What each part of U0653 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 53 | The exact fault in that area. |
What to do next
- Note U0653 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 U0653
What does U0653 mean?
U0653 means "Lost Communication With EGR Sensor C". On GM's 2025 diesel with high- and low-pressure EGR (table 25OBDG04B), EGR sensor C is the SENT position sensor of the low-pressure valve, which as usual for such loops takes exhaust after the particulate filter and feeds it ahead of the compressor. It is a generic code, so it means the same on every make.
Is it safe to drive with U0653?
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 U0653 fail an emissions test?
Yes, it can. U0653 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 U0653 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3.5 hours of work. This is a job for a workshop.
Will U0653 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.