Network, generic

U05B4 Invalid Data Received From Driver Monitoring System Module

Check engine lightUsually off

EmissionsNot relevant

Drive cycleNot required

Limp modeNo

A driver monitoring system films the driver's face with an infrared camera to judge attention and drowsiness. Toyota launched it in 2006, Cadillac relies on one to allow hands-free Super Cruise, and EU Regulation 2019/2144 covers it. Subaru stores up to five driver profiles in its DMS control unit and asks technicians to save them before service (bulletin 07-175-20); Stellantis lists a driver monitoring system module (DMSM) among the ADAS units of the 2025 Grand Cherokee that drop features after a deep battery discharge (STAR S2408000086, charge above 90 %, then ten minutes of bus sleep). U05B4 means its gaze or status messages reach the ADAS controller but are invalid. No manufacturer documents U05B4 publicly; hands-free and lane functions are then usually withdrawn. U02B3 covers a silent module.

Likely causes

Low 12 V state of charge or recent battery replacement

Camera or infrared emitters covered, dirty or misaligned

Module software or calibration not matching the ADAS controller

Driver monitoring module internally defective

Symptoms

Hands-free or lane assistance not available
Driver attention warning inactive or triggered without reason
Service message for driver assistance in the cluster

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€50–1,200

Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

driver monitoring module

Related codes

U02B3

References: static.nhtsa.gov, static.nhtsa.gov, en.wikipedia.org, bosch-mobility.com.