U0243: Lost Communication With Parking Assist Control Module B

What it means

A control module has stopped receiving expected messages from parking assist control module B. The code identifies the communication loss; parking-assist functions may be affected.

At a glance

• Usually lights the warning light of the system that lost communication

How it works

Parking assist control module B processes information for the parking-assist functions assigned to it and communicates status with other modules over the vehicle network. U0243 sets when a module expecting its messages no longer receives them, which can make those parking-assist functions unavailable.

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

• Parking-assist functions may be unavailable
• A warning may appear depending on the vehicle

How to diagnose it

1. Scan all modules and review freeze-frame or event data for other communication faults that could point to a wider network problem.
2. Check which parking-assist functions are unavailable and whether the vehicle displays a parking-assist warning.
3. Inspect module B's connector and nearby network wiring for damage, corrosion, water intrusion, or loose terminals.
4. Check module B's power and ground circuits according to the manufacturer's procedure.
5. Test the network wiring to parking assist control module B for opens, shorts, and poor connections using the wiring diagram.
6. If the power, ground, and network circuits pass, follow the manufacturer's diagnostic procedure to assess module B.

Common fixes

• Reconnect or clean a loose or corroded module B connector.
• Repair damaged network wiring or connector terminals leading to parking assist control module B.
• Repair the module's power or ground supply fault.
• Replace module B if circuit checks pass and diagnostics confirm internal failure.

Can I keep driving?

You can generally drive if the vehicle is otherwise operating normally, but park slowly and check the area directly because parking assistance may not be available. Do not rely on sensors or alerts that are not working.