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U0231 Lost Communication With Rain Sensing Module

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0231 shows that the rain sensing module on the windscreen, an optical unit that registers droplets and often ambient brightness too, no longer answers. It usually sits on a LIN line below a body or wiper controller, which stores the code. FCA bulletin 08-050-22 Rev. A (Jeep Grand Cherokee WL 2021) lists U0231-00 among a group of LIN lost communication codes that appear without a MIL and are cured by new body control module software. When the sensor is silent, automatic wiping falls back to the fixed stages and, where the same unit measures light, the automatic headlamp function can be lost. After a windscreen replacement, a loose plug behind the mirror cover is a classic cause. U0532 covers invalid data from the same sensor.

Likely causes

Sensor plug not seated after windscreen or mirror work
Body control module software (FCA 08-050-22)
LIN wire damaged in the headliner or A-pillar
Rain sensing module faulty

Symptoms

  • Automatic wipers inoperative, manual stages still work
  • Automatic headlamps not switching

Repair estimate

DifficultyEasyDIY possible
Parts and labour€0–300
Time0.2–1.5 h

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

Parts involved

rain light sensorlin wiring

Related codes

U0532U0140

References: static.nhtsa.gov, en.wikipedia.org.