HomeTrouble CodesU0231

U0231 — Lost Communication Rain Sensing Module

Generic OBD-II · all makesNetwork / communication

Code U0231 indicates that the vehicle's onboard diagnostic system has detected a loss of communication with the Rain Sensing Module. This means the module is not sending or receiving data over the vehicle's communication network, typically disabling automatic wiper functions.

Symptoms

What causes it — most likely first

1. Rain Sensing Module Failure

Internal electronic failure within the module prevents it from communicating with the rest of the vehicle network.

2. Wiring Harness Damage

Frayed, broken, or corroded wires between the module and the communication bus disrupt signal transmission.

3. Power Supply Issue

A blown fuse or faulty ground connection prevents the module from powering on.

4. Poor Connector Seating

Loose or oxidized pins at the module connector create an open circuit or high resistance.

5. CAN Bus Interference

Other faults on the communication network may be blocking the data stream from the rain sensor.

6. Control Module Fault

A failure in the Body Control Module (BCM) or PCM that manages the network interface, though this is rare.

How it's diagnosed

  1. Verify that automatic wiper functions are unresponsive while manual controls still work.
  2. Inspect the fuse panel for any blown fuses associated with the rain sensor or wiper system.
  3. Perform a visual inspection of the wiring harness for signs of chafing, corrosion, or rodent damage.
  4. Use a multimeter to verify that the rain sensing module is receiving the correct voltage and has a solid ground.
  5. Check the integrity of the CAN bus wiring for shorts or open circuits using a digital multimeter.
  6. Utilize a diagnostic scan tool to check for other communication codes that might indicate a broader network failure.

Code facts & related codes

SystemNetwork / communication
StandardizationSAE generic — identical on every make

Frequently asked

Does this code mean I need to replace my PCM?

No. U0231 is specifically related to the rain sensing module. It is highly unlikely that the PCM is the cause; the issue is almost always the module itself, its power supply, or the wiring.

Can a windshield replacement cause this code?

Yes. If the rain sensor is not properly seated against the new glass or if the sensor was damaged during the installation process, communication errors may occur.

Will my wipers stop working completely?

Usually not. In most vehicles, manual wiper controls are designed to operate independently of the rain sensing module as a fail-safe.