What it means
A receiving module detected implausible data from running board control module B. Position or motor current values fail plausibility checks and are rejected.
How it works
Running board control module B reports the board's position and motor-current status over the vehicle network. Receiving modules check those values for plausibility; U0552 sets when a module rejects data attributed to board module B, and the powered step may stop operating.
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 U0552, related communication codes, and freeze-frame details to identify which module rejected running board module B's data.
- Check live data for module B's communication status and compare reported board position or motor-current changes with the board's movement.
- Inspect running board B for obstruction, binding, impact damage, and loose hardware, then check its module connector, power, ground, and network wiring.
- Check whether the fault followed module replacement or software work and verify that module B's configuration matches the vehicle.
- If the board and wiring are sound, use manufacturer diagnostic information to assess module messages and gateway routing before replacing parts.
Common fixes
- Remove debris or an obstruction that prevents running board B from moving freely.
- Repair a loose, corroded, or damaged connector or wiring at module B.
- Restore a poor power or ground connection to the running board module.
- Correct an incompatible module configuration or software mismatch after replacement.
- Repair or replace module B if its position or motor-current data remains implausible with sound wiring and a free-moving board.
Can I keep driving?
Driving is usually possible, but running board B may remain extended, retracted, or move unpredictably. Check that it is secure and clear of the road before driving, and keep clear while the powered board is operating.
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.