What it means
A module reports a software version mismatch with parking assist module A — typically after replacing one of the modules without programming the new unit to match the rest of the network.
How it works
A vehicle controller checks whether its software is compatible with parking assist control module A, which supplies information used by parking assistance features. U031D sets when module A reports a software version or configuration that the checking controller does not recognize as compatible.
Common causes
Most likely first.
- Module replaced without programming
- Wrong part number for the vehicle
- Gateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules and save freeze-frame or event data, identifying which controller logged U031D and whether parking assist or network codes accompany it.
- Ask whether parking assist control module A or a related controller was recently replaced, updated, or configured, as an unprogrammed change is a common trigger.
- Inspect module A's connector and harness for loose connections, corrosion, moisture, or damage that could interrupt its network communication.
- Use a scan tool to read parking assist module A's identity, software version, and configuration, then compare them with the vehicle's required information.
- Check gateway and network fault records for message-routing problems affecting parking assist module A.
- Restore the correct software and configuration using the manufacturer's procedure, then rescan and verify that U031D stays cleared.
Common fixes
- Secure or repair a loose or corroded connector at parking assist control module A.
- Program or configure a replacement parking assist module A for the vehicle.
- Fit the correct module if the installed part is incompatible.
- Correct gateway configuration or routing if it is disrupting messages to module A.
Can I keep driving?
If only parking assistance is affected, you can generally drive while taking extra care when reversing and parking; do not rely on sensors or warnings that may be unavailable. Stop and reassess if other vehicle systems or safety warnings are also affected.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.