U0221: Lost Communication With Door Switch G

What it means

The reporting module has lost communication with door switch G. It sets this code when expected switch messages from that module are not received for a specified time.

How it works

Door switch G sends status messages across the vehicle network so other modules can respond to that door being open or closed. U0221 records when the reporting module stops receiving the expected messages from switch G for the required interval.

Common causes

Most likely first.

1. Switch power or ground fault
2. Damaged or corroded wiring or connectors
3. CAN bus fault
4. Door switch G failure
5. Low battery voltage

Symptoms

• Door status may display incorrectly
• Door warning or courtesy light may malfunction
• Other communication codes

How to diagnose it

1. Scan all modules and check freeze-frame details for low voltage or other communication faults that could explain the loss of switch G messages.
2. Operate the door associated with switch G and observe whether its door status, warning, and courtesy light respond correctly.
3. Inspect switch G's connector and the moving door harness for corrosion, pulled wires, chafing, or loose terminals.
4. Use the vehicle wiring diagram to test switch G's power and ground and check its network wiring for opens or shorts.
5. If the circuit checks pass, test switch G and its communication with the manufacturer's diagnostic method.

Common fixes

• Recharge the battery if system voltage was low when the code set.
• Secure or clean the switch G connector if its contact is poor.
• Repair damaged wires or restore switch G's power or ground.
• Repair a verified network wiring problem on the switch G circuit.
• Replace switch G if testing confirms it is faulty.

Can I keep driving?

If the associated door latches securely, a short drive is generally possible, but check the door before leaving. The vehicle may show the wrong status for that door or operate its warning and courtesy light incorrectly.