U0261: Lost Communication With Seat Control Switch Module B

What it means

A control module has stopped receiving expected messages from seat control switch module B. The code identifies the communication loss; seat controls routed through that module may be affected.

How it works

Seat control switch module B sends seat-switch requests over the vehicle network to the systems that operate the seat. U0261 sets when another module stops receiving expected messages from module B specifically; it does not by itself indicate a fault in seat control switch module A or in every seat function.

Common causes

Most likely first.

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

Symptoms

• Seat controls routed through the module may be unavailable or limited
• A warning may appear depending on the vehicle

How to diagnose it

1. Scan all modules and record whether U0261 is current, its freeze-frame context, and any companion network or low-voltage codes.
2. Check which seat controls are inoperative and confirm which switches are assigned to module B for this vehicle.
3. Inspect module B's connector and wiring for looseness, corrosion, liquid exposure, chafing, or bent pins.
4. Test module B's power and ground using the manufacturer's circuit information to determine whether the module is simply unpowered.
5. If supply circuits are sound, test the network wiring to module B for an open or short before replacing the module.

Common fixes

• Reconnect or clean a poor connection at seat control switch module B.
• Repair chafed or broken bus wiring to module B.
• Repair a failed power or ground supply.
• Replace and configure module B if it does not communicate despite verified circuits.

Can I keep driving?

The code generally affects seat controls routed through module B, not engine operation. Avoid adjusting the seat while moving, and do not drive if you cannot secure a safe seating position.