U025C: Lost Communication With Special Purpose Vehicle Control Module D

What it means

A control module has stopped receiving expected messages from special purpose vehicle control module D. The code identifies the communication loss; upfitted functions controlled by that module may be affected.

How it works

Special purpose vehicle control module D manages its assigned upfitted equipment and communicates its status to other modules over the network. U025C sets when a monitoring module stops receiving the expected messages from module D.

Common causes

Most likely first.

1. Bus wiring open or shorted
2. Module without power or ground
3. Module failed

Symptoms

• Functions controlled by the special purpose module may be unavailable
• A communication fault may be stored

How to diagnose it

1. Record freeze-frame data and scan all modules for communication faults to establish whether module D alone has dropped off the network.
2. Check which special purpose or upfitted functions are unavailable and confirm that they are assigned to module D on this vehicle.
3. Inspect module D's connectors and network wiring for loose connections, corrosion, damaged wires, or evidence of an open or short circuit.
4. Verify module D's power and ground circuits using the manufacturer's procedure before concluding that the module has failed.
5. With its supplies confirmed, test the network wiring to module D for opens or shorts following the manufacturer's procedure.

Common fixes

• Secure a loose connector at special purpose vehicle control module D.
• Repair damaged or corroded network wiring and terminals serving module D.
• Restore a missing power or ground connection to module D.
• Replace module D if its power, ground, and network wiring are sound but communication remains lost.

Can I keep driving?

Driving guidance depends on the upfitted functions assigned to module D. Avoid using affected equipment and do not drive if its loss compromises a function needed for safe vehicle operation.