U05B4 code meaning
Invalid Data Received From Driver Monitoring System Module
What U05B4 means
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 No manufacturer documents U05B4 publicly; hands-free and lane functions are then usually withdrawn.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.
U05B4 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U05B4
- Hands-free or lane assistance not available
- Driver attention warning inactive or triggered without reason
- Service message for driver assistance in the cluster
Common causes of U05B4
- Most likelyLow 12 V state of charge or recent battery replacement
- PossibleCamera or infrared emitters covered, dirty or misaligned
- PossibleModule software or calibration not matching the ADAS controller
- Less likelyDriver monitoring module internally defective
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Driver monitoring module
What each part of U05B4 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B4 | The exact fault in that area. |
What to do next
- Note U05B4 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U05B4
What does U05B4 mean?
U05B4 means "Invalid Data Received From Driver Monitoring System Module". A driver monitoring system films the driver's face with an infrared camera to judge attention and drowsiness. It is a generic code, so it means the same on every make.
Is it safe to drive with U05B4?
U05B4 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U05B4 fail an emissions test?
U05B4 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U05B4 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will U05B4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.