U0442Invalid Data Received From ECM/PCM B
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- ECM/PCM B stands for a second engine or powertrain controller where a car carries more than one such unit; U0442 means its frames reach a receiver with invalid content, while U0115 means they stop arriving. Mazda applies the code in its own way: bulletin 01-015/18 for the 2018 Mazda6 and CX-5 and the 2019 CX-3 and MX-5 describes the TCM of automatic models flagging invalid PCM data, together with P061B and U0401, when the driver lets go of the brake during cranking. The PCM then enters a fail-safe mode with limited engine speed, and new PCM software cures the false detection. Mercedes-Benz lists U044287 with U014687 when a software conflict in the 48 V battery switches on the check engine light (LI54.21-P-078926). Expect the MIL and, depending on design, reduced power.
- What you may notice
- Check engine light on
- Fail-safe mode with limited engine speed or lack of power
- Transmission codes stored alongside engine codes
- Likely causes
- LikelyControl logic in the engine or powertrain software too sensitive, update available
- PossibleSoftware levels of sending and receiving units do not match after an update
- RareBus wiring, connector or supply fault at the second powertrain controller
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €80 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.