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U0216 — Lost Communication Door Switch B

Generic OBD-II · all makesNetwork / communication

Code U0216 indicates that the vehicle's communication network has lost contact with the Door Switch B sensor or module. This is typically a network-related fault where the Body Control Module (BCM) is no longer receiving data signals from the specified door switch.

Symptoms

What causes it — most likely first

1. Faulty Door Switch B

Internal electrical failure of the switch assembly preventing it from sending signals.

2. Damaged Wiring in Door Boot

Wiring harness fatigue or breakage occurring where the door wires flex through the rubber boot.

3. Corroded Connectors

Moisture intrusion leading to corrosion on the pins of the door switch or the BCM connector.

4. Blown Fuse

A blown fuse providing power to the door module or communication circuit.

5. Body Control Module (BCM) Failure

Internal hardware or software fault within the BCM preventing communication with the door network.

How it's diagnosed

  1. Inspect the door switch for physical damage or loose mounting.
  2. Examine the wiring harness inside the door bellows for frayed or broken wires.
  3. Perform a continuity test between the door switch connector and the BCM.
  4. Verify that the door switch is receiving the correct reference voltage and ground.
  5. Check for the presence of communication signals using an oscilloscope or scan tool.

Code facts & related codes

SystemNetwork / communication
StandardizationSAE generic — identical on every make
Related codesU0210 — Lost Communication Seat Control ModuleU0211 — Lost Communication Seat Control ModuleU0212 — Lost Communication Steering Column ConU0213 — Lost Communication Mirror Control ModuU0214 — Lost Communication Remote Function ActU0215 — Lost Communication Door Switch

Frequently asked

Does this code mean the door lock is physically broken?

Not necessarily. The code refers to the communication of the switch signal, not the mechanical operation of the lock.

Should I replace the Body Control Module (BCM) to fix this?

No. Communication codes are most frequently caused by wiring failures or the peripheral switch itself; the BCM is rarely the cause and should only be replaced after all wiring is verified.

Can a broken wire in the door hinge cause this code?

Yes, this is one of the most common causes due to the constant bending of the wires every time the door is opened and closed.