U042CInvalid Data Received From Chassis Control Module B
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U042C refers to a second chassis controller, labelled B, where chassis tasks are split between two units. It is stored when that module's frames still arrive but carry a bad counter, checksum or implausible values. No manufacturer documents U042C or the B module publicly; the only public assignment found concerns module A, which GM's 2020 transmission tables equate with the integrated chassis control module. CARB asks emission-related controllers to flag faulty digital communication as well as its absence, which mirrors the pair U012B and U042C, although a chassis unit usually lies outside that rule. B alone points to that module or its harness, B with U042B to shared supply, gateway or bus wiring. A MIL is not expected; chassis messages are likely. U012B is lost contact.
- What you may notice
- Chassis or suspension warning in the cluster
- Chassis function handled by module B inactive
- Likely causes
- PossibleSoftware fault in chassis module B or the receiver
- PossibleSupply, ground or gateway problem affecting the module's messages
- RareChassis control module B faulty
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.