What Does U0243 Mean?
Communication has been lost between the vehicle's main network controller and the secondary parking assist control module. This fault prevents parking assist features from functioning and indicates a network communication problem.
Common Causes
30%
Corroded or damaged connector at parking assist module B
25%
Failed Parking Assist Control Module B
25%
Damaged wiring harness or CAN bus wiring
15%
Loss of power or ground to parking assist module
5%
Water intrusion or moisture in module causing internal failure
Diagnostic Steps
1
Step 1: Locate parking assist control module B (often in rear bumper area) and inspect for physical damage or water intrusion
2
Step 2: Check all fuses related to parking assist system and verify power and ground at module connector
3
Step 3: Inspect connector for corrosion, bent pins, or moisture and clean/repair as needed
4
Step 4: Test CAN bus communication lines for proper voltage and continuity to other modules
5
Step 5: Monitor live data while wiggling harness to identify intermittent wiring faults; replace module if all wiring tests pass
Estimated Repair Cost
$200 - $900
Parts + labor, varies by vehicle and location
Communication has been lost between the vehicle's main network controller and the secondary parking assist control module. This fault prevents parking assist features from functioning and indicates a network communication problem.
The most common cause of U0243 (Lost Communication With Parking Assist Control Module "B") is: Corroded or damaged connector at parking assist module B
Typical repair costs for U0243 range from $200 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of parking assist functions (sensors/camera) increases risk of low-speed collisions while parking. Vehicle remains safe to drive but requires increased driver attention.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0243 to identify the root cause.
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Quick Info
Category
Network
System
Parking Assist System / Communication Network
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
