Network, generic

U023D Lost Communication With Front Distance Range Sensor - Left

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

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.

Likely causes

Connector or harness at the left front corner damaged (collision, bumper work)
Road salt corrosion at the radar plug
Left front corner radar faulty

Symptoms

  • Adaptive cruise control unavailable
  • Front cross traffic or collision assist limited

Repair estimate

DifficultyHardWorkshop job
Parts and labour€50–1,200
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

front distance sensor lcan bus

Related codes

U023EU0235U043B

References: gsi.ext.gm.com, en.wikipedia.org.