What it means
A receiving module detected implausible data from suspension control module B. Damper command, ride-height or air-pressure values fail plausibility checks and are rejected.
At a glance
- Usually lights the warning light of the system that lost communication
- The engine or gearbox may go into limp mode
How it works
Suspension control module B reports suspension data such as damper commands, ride height, or air pressure to other modules. U043A sets when a receiving module rejects data from module B as implausible. A module or sensor fault, software mismatch, or CAN routing problem can disable or limit the suspension functions that depend on those messages.
Common causes
Most likely first.
- Module internal fault or sensor input drift
- Software version mismatch after replacement
- 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 U043A, suspension codes, and freeze-frame data to identify which module rejected suspension control module B's messages.
- Read module B live data for damper command, ride height, and air pressure where fitted, looking for missing or inconsistent values.
- Inspect module B connectors, suspension sensors and actuators, air lines where fitted, grounds, and CAN wiring for damage or leaks.
- Check for recent suspension-module replacement or programming and verify software compatibility and configuration.
- Test relevant sensor and actuator circuits and CAN communication to the manufacturer's specification before replacing module B.
Common fixes
- Repair a loose or corroded module B connector or ground.
- Repair damaged wiring, a leaking air line, or a faulty connection identified by inspection.
- Correct software or configuration incompatibility in suspension control module B.
- Repair a confirmed gateway or CAN network fault.
- Replace a sensor, actuator, or module B only after tests identify the failed component.
Can I keep driving?
The suspension may be in a limited mode, and ride height or damping can be affected. Reduce speed, avoid heavy loads and rough roads, and stop if the vehicle sits abnormally low, handles poorly, or shows a stop warning.
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.