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DTC codes / U02xx · Lost communication with a control module / U0215

U0215Lost Communication With 'Door Switch A'

U0215 is a communication fault that sets when a control module on the vehicle's Controller Area Network (CAN) bus stops receiving messages from the module or sensor designated as 'Door Switch A'. The computer has detected a loss of the periodic data signal that tells it whether a specific door is open or closed, not a failure of the switch itself.

SystemNetwork
Code typeGeneric (all makes)
SeverityLow
Fix difficultyIntermediate
AreaLost communication with a control module

Symptoms you may notice

  • Illumination of the malfunction indicator lamp (check engine light) or a body control warning message
  • Interior dome light staying on or failing to come on when a door is opened
  • Door-ajar warning chime or message appearing when all doors are actually closed
  • Remote keyless entry or push-button start behaving intermittently because the body computer cannot confirm door status
  • Battery drain from a module staying awake due to a false door-open signal
  • Often no symptoms besides the warning light, with all door functions working normally

Common causes, most likely first

  1. Damaged or corroded wiring harness at the door hinge area where flexing occurs
  2. Failed door latch or door switch assembly on the affected door
  3. Loose, backed-out, or corroded connector pins at the door switch or body control module
  4. Water intrusion into the door cavity or body control module connector causing corrosion
  5. Failed body control module (BCM) or door control module that is not transmitting the door status message
  6. CAN bus wiring fault between the door module and the body computer, including chafed or shorted twisted pair
  7. Low battery voltage or poor ground connection causing intermittent module communication

How to diagnose and fix it

  1. Verify battery state of charge and clean battery terminals and ground straps before any communication diagnosis
  2. Connect a scan tool and read all modules for U0215 and related communication codes to identify which module is reporting the loss
  3. Inspect the door hinge wiring harness and door connector for chafed insulation, broken strands, or corrosion
  4. Check the door switch or latch assembly for proper operation and continuity using a multimeter
  5. Perform a voltage drop and resistance test on the CAN bus wiring between the door module and the body control module
  6. Substitute a known-good door switch or latch assembly to confirm the fault follows the component
  7. If wiring and switch test good, diagnose the body control module power, ground, and communication circuits before replacement

Door switch codes that fool good technicians

  • The code names 'Door Switch A' but the actual failure is usually in the wiring at the door hinge boot, not the switch itself, so replacing the latch first often wastes money.
  • A door switch that tests fine with a multimeter can still set U0215 because the body computer expects a pulsed or multiplexed signal that a simple continuity test cannot confirm.
  • Water leaks into the door or footwell corrode the body control module connectors and mimic a failed door switch, so always check for damp carpets and green pins.
  • U0215 can be stored by a module that is simply not powered up due to a blown fuse or poor ground, which looks like a communication failure but is actually a power supply fault.
  • After repairing the wiring or switch, the code may remain stored until the body control module sees several clean door-open and door-close cycles, so do not condemn the repair prematurely.

Can I keep driving with U0215?

The vehicle remains safe to drive because the fault affects door status reporting rather than engine, braking, or steering control. Avoid leaving the vehicle unattended for long periods until repaired, since a false door-open signal can drain the battery, and do not rely on the door-ajar warning to confirm the doors are latched.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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

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