# U0198 on the 2027 Mazda CX\-90

The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.

Nobody has written a description of this code yet.

## Bulletins for this model year that name U0198

- [11037632](https://open.wenmarpro.com/bulletins/11037632), 2026-10-01: DESCRIPTION Some customers may experience a message "TCU Malfunction. Have the Vehicle Inspected" in the instrument cluster. Additional symptoms that may occur: Connected Vehicle One Time Passcode \(OTP\) may fail. Connected Vehicle Remote functions may fail. The following DTC's may be stored: B1252:87\-8B:TCU \- COMMUNICATION ERROR WITH CONNECTIVITY MASTER UNIT \(CMU\) U0198:00\-03:CMU \- COMMUNICATION ERROR WITH EMERGENCY CALL UNIT/TELEMATICS COMMUNICATION UNIT REPAIR PROCEDURE 1. Verify the concern. 2. Check if any of the following DTCs are stored: B1252:87\-8B:TCU \- COMMUNICATION ERROR WITH CONNECTIVITY MASTER UNIT \(CMU\) U0198:00\-03:CMU \- COMMUNICATION ERROR WITH EMERGENCY CALL UNIT/TELEMATICS COMMUNICATION UNIT Are the following DTCs stored? YES: Proceed to next step. NO: This service information does not apply. Continue troubleshooting using MGSS.