U049A: Invalid Data Received From Door Control Module A

What it means

A control module received invalid data from door control module A. The code identifies a data validity fault; the specific affected function depends on the vehicle.

How it works

Door control module A reports door-related status and control data to other modules over the vehicle network. U049A sets when a receiving module judges data from door module A invalid; the code names module A but does not identify which door function or location without vehicle-specific information.

Common causes

Most likely first.

1. Fault in the transmitting module
2. Network wiring or connector fault
3. Module power or ground fault
4. Software or configuration mismatch

Symptoms

• One or more functions controlled by the affected door module may not work correctly
• Related communication codes or system warnings may appear

How to diagnose it

1. Use a scan tool to save freeze-frame details and check whether U049A returns, since an intermittent network fault may not be active now.
2. Check which modules report U049A and look for related door or network codes to narrow down the affected functions.
3. Inspect door module A's connectors and wiring, including any wiring through a door jamb, for loose pins, corrosion, damage, or chafing.
4. Check the module's power and ground using the manufacturer's diagnostic procedure, since supply problems can disrupt its network data.
5. If wiring and supplies are sound, use vehicle-specific tests to identify the door associated with module A and assess its software and operation.

Common fixes

• Reconnect or clean a loose or corroded door module A connector.
• Repair damaged wiring to the module, including broken conductors in a door-jamb harness.
• Repair a poor module power or ground connection.
• Correct software or configuration if vehicle-specific service information calls for it.
• Replace door control module A if testing confirms it is faulty.

Can I keep driving?

Door-related functions may be unreliable, and the affected feature varies by vehicle. Check that doors latch securely and avoid relying on electrically operated locks or windows until the fault is understood.