AutoCodes – Generic – U0231

U0231 Code - Lost Communication With Rain Sensing Module

Quick Answer

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Common causes include Faulty Rain Sensing Module, Rain Sensing Module harness is open or shorted, Rain Sensing Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U0231 indicates Lost Communication With Rain Sensing Module.
Common causes: Common causes include Faulty Rain Sensing Module, Rain Sensing Module harness is open or shorted, Rain Sensing Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 13,113

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 04, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U0231 Description

A Controller Area Network (CAN) is a vehicle bus standard designed to interconnect automotive devices without a host computer. Operating information and commands are exchanged among the devices. The devices have programmed information about what messages are needed to be exchanged on the serial data circuits. CAN bus uses two dedicated wires for communication. The wires are called CAN high and CAN low. When the CAN bus is in idle mode, both lines carry 2.5V. When data bits are being transmitted, the CAN high line goes to 3.75V, and the CAN low drops to 1.25V, thereby generating a 2.5V differential between the lines. Since communication relies on a voltage differential between the two bus lines, the CAN bus is NOT sensitive to inductive spikes, electrical fields, or other noise. The Diagnostic Trouble Code (DTC) sets when a periodic message from the Rain Sensing Module has not been received.

OBDII Code U0231 - Lost Communication With Rain Sensing Module - AutoCodes.com — U0231 Code - Lost Communication With Rain Sensing Module

What does this mean?

What are the Possible Causes of the DTC U0231?

Faulty Rain Sensing Module
Rain Sensing Module harness is open or shorted
Rain Sensing Module circuit poor electrical connection

How to Fix the DTC U0231?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U0231 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the U0231 code?

Need more information on how to fix the U0231 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0231 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U0231 Buick — Lost Communication With Rain Sensor Module
U0231 Cadillac — Lost Communication With Rain Sensor Module
U0231 Chevrolet — Lost Communication With Rain Sensor Module
U0231 Ford — Lost Communication With Rain Sensing Module
U0231 GMC — Lost Communication With Rain Sensor Module
U0231 Lincoln — Lost Communication With Rain Sensing Module
U0231 Mercury — Lost Communication With Rain Sensing Module

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U0231 Code

1. What does the OBDII code U0231 mean?

U0231 indicates a lost communication fault between the vehicle's main control modules and the Rain Sensing Module (RSM), which manages automatic wiper functions.

2. What are common symptoms of the U0231 code?

Symptoms include non-functional or erratic behavior of automatic wipers, a check engine light or other warning lights, and possible loss of rain-sensing features.

3. What causes the U0231 code to appear?

Common causes include a faulty Rain Sensing Module, damaged wiring or connectors, issues with the CAN bus network, or a malfunctioning Body Control Module (BCM).

4. Can I still drive my car with a U0231 code?

Yes, your car is typically drivable, but rain-sensing wipers may not function, which could affect visibility during rain.

5. How can I diagnose the U0231 code?

Use a scan tool to verify the code, inspect the wiring and connectors to the Rain Sensing Module, and test for continuity or breaks in the CAN bus network.

6. What should I check first when troubleshooting U0231?

Start by inspecting the Rain Sensing Module's wiring and connectors for corrosion, damage, or loose connections.

7. How much does it cost to fix a U0231 code?

Repair costs can vary, ranging from $50 for simple wiring repairs to $500 or more if the Rain Sensing Module needs replacement.

8. Can a low battery cause the U0231 code?

Yes, a weak or failing battery can cause communication issues with the Rain Sensing Module and trigger the U0231 code.

9. Do I need to replace the Rain Sensing Module to fix U0231?

Not always. The issue could be with wiring, connectors, or the CAN bus network rather than the module itself.

10. How can I prevent the U0231 code from recurring?

Regularly inspect and maintain your vehicle's electrical connections, ensure the battery is in good condition, and address any communication faults promptly.