Short Range Radar Conditions in Highly Reflective Environments

Some 2021 Tahoe, Suburban, Yukon and Escalade models equipped with the Reverse Automatic Braking system (RPO UVZ) may have a Service Driver Assist message displayed on the Driver Information Center (DIC) along with DTC U3000 49 (Control Module Internal Malfunction). These conditions may be caused by an issue with the Short Range Radar (SRR) due to highly reflective environments. Some temporary faults that trigger DTC U3000 49 may be detected while the radar is actively radiating.

Reverse Automatic Braking alerts the driver when a collision with a detected object directly behind the vehicle is imminent and, if necessary, automatically applies hard emergency braking. The system uses the Image Processing Module and one or two Short Range Radar Sensors, located behind the rear fascia, as well as the ultrasonic Parking Assist Sensors to identify objects behind the vehicle. (Fig. 5)


Fig. 5


If DTC U3000 49 is set, reprogram the Short Range Radar with the latest calibrations and verify the condition is no longer present. Refer to Short Range Radar Sensor in the appropriate Service Information.

If the condition is still present after reprogramming, there may be an issue with the X270 headliner harness to the instrument panel harness. (Fig. 6)


Fig. 6


Check for any loose terminals in the X270 harness. (Fig. 7) Repair as necessary.


Fig. 7


For additional information, refer to Bulletin 21-NA-243.


– Thanks to Hassan Abdallah

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