A faulty door switch C itself, such as a worn plunger, corroded internal contacts, or a broken switch housing.; Damaged or chafed wiring in the door jamb boot, where the harness flexes every time the door opens and closes.; Loose, corroded, or unseated electrical connector at the door switch or at the module that reads the switch.; A blown fuse or poor ground connection that supplies power or ground to the door switch circuit.; Water intrusion into the door switch or connector, leading to corrosion and intermittent signal loss.; A failed body control module (BCM) or door control module that is no longer transmitting or receiving the door switch message on the CAN bus.; CAN bus wiring faults, such as an open or short in the twisted pair, that disrupt communication between modules.

DTC codes / U02xx · Lost communication with a control module / U0217

U0217Lost Communication With 'Door Switch C'

Q: What does code U0217 mean?

Lost Communication With 'Door Switch C'. U0217 is a generic communication fault indicating that a control module on the vehicle's controller area network (CAN) bus has lost contact with the module or sensor designated as 'Door Switch C'. The computer detected that expected periodic messages from that door switch input have stopped arriving within the required time window, which sets the code and usually triggers a warning light or a message on the driver information display.

U0217 is a generic communication fault indicating that a control module on the vehicle's controller area network (CAN) bus has lost contact with the module or sensor designated as 'Door Switch C'. The computer detected that expected periodic messages from that door switch input have stopped arriving within the required time window, which sets the code and usually triggers a warning light or a message on the driver information display.

SystemNetwork

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaLost communication with a control module

Symptoms you may notice

Often no symptoms besides the warning light, because the affected door switch may only control a convenience feature.
The interior dome light may fail to turn on or off when a specific door is opened or closed.
The driver information display may show a door ajar warning even when all doors are fully closed.
Keyless entry or push-button start may behave erratically if the vehicle uses door switch status for authentication.
The vehicle may not automatically lock or unlock doors according to the door switch input.
Battery drain may occur if the module interprets a missing door switch signal as a door left open.

Common causes, most likely first

A faulty door switch C itself, such as a worn plunger, corroded internal contacts, or a broken switch housing.
Damaged or chafed wiring in the door jamb boot, where the harness flexes every time the door opens and closes.
Loose, corroded, or unseated electrical connector at the door switch or at the module that reads the switch.
A blown fuse or poor ground connection that supplies power or ground to the door switch circuit.
Water intrusion into the door switch or connector, leading to corrosion and intermittent signal loss.
A failed body control module (BCM) or door control module that is no longer transmitting or receiving the door switch message on the CAN bus.
CAN bus wiring faults, such as an open or short in the twisted pair, that disrupt communication between modules.

How to diagnose and fix it

Verify the code with a scan tool and check for related communication codes in all modules to confirm the fault is isolated to door switch C.
Inspect the door switch C for physical damage, corrosion, or a stuck plunger, and test its continuity with a multimeter while operating the door.
Check the wiring harness in the door jamb boot for chafed, broken, or corroded wires, and repair any damage found.
Measure voltage and ground at the door switch connector with the door open and closed to confirm power and ground are present.
Inspect and reseat the connector at the module that reads the door switch, looking for bent pins or corrosion.
Check the fuses and grounds that serve the door switch circuit and the body control module.
If the switch, wiring, and power are good, perform a network communication test and consult the factory service information for module diagnostics before replacing any module.

Door switch faults that mimic module failures

A door switch that tests good on the bench can still set U0217 if the door jamb wiring is intermittent, so always wiggle-test the harness while watching live data.
The code names 'Door Switch C' but many vehicles use a single switch per door; confirm which door the manufacturer labels as C before ordering parts.
A weak or failing battery can cause multiple U-codes, including U0217, because modules drop offline during cranking; clear the codes and retest after charging the battery.
Aftermarket alarms or remote start systems tapped into door switch wiring are a common cause of communication loss that owners overlook.
U0217 can be stored in a module that is not the body control module, so check all modules for the code and follow the network topology rather than replacing the first module you see.

Can I keep driving with U0217?

The vehicle is generally safe to drive because the fault affects a convenience or monitoring circuit rather than engine, braking, or steering operation. Avoid relying on automatic door locking or alarm features until the fault is repaired, and address any battery drain promptly if the vehicle sits for long periods.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.