U0237: Lost Communication with Sunroof Assembly Control Module

What it means

A control module has stopped receiving expected messages from the sunroof assembly control module. The code identifies the communication loss; sunroof functions may be unavailable or limited.

How it works

The sunroof assembly control module manages or reports sunroof operation, depending on the vehicle. U0237 is set when another module stops receiving the expected network messages from that sunroof module.

Common causes

Most likely first.

1. Loss of power or ground to the module
2. Open, shorted, or damaged network wiring or connector
3. Failed module

Symptoms

• Sunroof functions may be unavailable or limited
• A communication fault may be stored; a warning may appear depending on the vehicle

How to diagnose it

1. Use a scan tool to record freeze-frame data and check whether U0237 is current, then see if other modules also report communication faults.
2. Check the sunroof switch and operation, noting whether the panel is in motion, unresponsive, or stops partway.
3. Inspect the sunroof control module connector and accessible wiring for looseness, corrosion, water intrusion, or damage, especially near the roof opening.
4. Check the module’s power and ground against the manufacturer’s wiring information.
5. Test the network wiring to the sunroof assembly control module for opens or shorts using the wiring diagram and manufacturer’s procedure.
6. If wiring and supplies are sound, use the manufacturer’s diagnostic procedure to confirm whether the sunroof module has failed.

Common fixes

• Reconnect or repair a loose or corroded sunroof module connector.
• Repair damaged wiring in the sunroof module’s network or power and ground circuits.
• Clear water or corrosion damage and correct any source of water entry found during inspection.
• Replace the sunroof assembly control module if tests confirm an internal failure.

Can I keep driving?

The vehicle is generally drivable, but the sunroof may not operate or may stop responding. Do not force the panel, and make sure it is secure and closed before driving in rain or at speed.