U023D code meaning
Lost Communication With Front Distance Range Sensor - Left
What U023D means
U023D means the left front distance range sensor, a short range corner radar that watches the area ahead and to the left of the bumper, has stopped reporting. Corner radars widen the field of view of the central long range radar, which helps adaptive cruise pick up cutting-in traffic. GM's 2025 summary 25OBDG04B is the only public manufacturer record: EOCM3 sets U023D when any of six left front radar bursts is missing for more than 0.20 s at 9-16 V, not in transport mode, not right after a reset and not during bus-off; adaptive cruise is disabled, Special Type C, no MIL. A crash repair or bumper work near the left headlamp is the usual suspect. U0235 is the centre sensor, U023E the right one, U043B invalid data.
U023D at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U023D
- Adaptive cruise control unavailable
- Front cross traffic or collision assist limited
Common causes of U023D
- Most likelyConnector or harness at the left front corner damaged (collision, bumper work)
- PossibleRoad salt corrosion at the radar plug
- Less likelyLeft front corner radar faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Front distance sensor lCAN bus
What each part of U023D means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3D | The exact fault in that area. |
What to do next
- Note U023D 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 U023D
What does U023D mean?
U023D means "Lost Communication With Front Distance Range Sensor - Left". U023D means the left front distance range sensor, a short range corner radar that watches the area ahead and to the left of the bumper, has stopped reporting. It is a generic code, so it means the same on every make.
Is it safe to drive with U023D?
U023D does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U023D fail an emissions test?
U023D is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U023D to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U023D clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.