DTC U0420; Abnormal Message From EPS Cm: Notes

WARNING: This page is about a different car, the 2017 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITION & POSSIBLE CAUSE

DTC	U0420:00	Abnormal message from EPS CM
DETECTION CONDITION		Correct data cannot be received from EPS CM
FAIL-SAFE FUNCTION		Illuminates the TCS/DSC indicator light and smart city brake support (SCBS) indicator light (amber) ^1 . Tire pressure monitoring system warning light ^1 illuminates after flashes. Inhibits the TCS, DSC, TPMS ^1 , smart city brake support (SCBS) ^1 controls. *: If equipped.
POSSIBLE CAUSE		EPS CM malfunction
SYSTEM WIRING DIAGRAM		Not applicable