B101D: How to Diagnose & Fix — ECU Hardware (Control Module Internal Hardware Performance)

The Safety Alert Seat uses haptic (vibration) motors in the left and right seat bolsters to pulse warnings for lane departure, blind spot, and forward collision. One side commonly stops vibrating (left or right only), or the system randomly switches between vibrate and chime. The documented weak point is a wire breaking where it enters the haptic motor assembly. Because GM ties this hardware into the driver-assist suite, a failed seat motor frequently also triggers a 'Service Driver Assist System' message.

The IntelliLink/MyLink touchscreen freezes and spontaneously reboots, losing control of radio, climate, navigation and Bluetooth, and often displays a black screen or a frozen backup-camera image. During a reboot, phone calls drop and the rear camera can go dark while in reverse - a visibility concern. Root causes include software glitches, outdated firmware, and occasionally loose display/camera wiring.

On later Encore GX models the Lane Keep Assist with Lane Departure Warning system applies an inappropriate steering torque that pulls the vehicle across the centerline rather than back into the lane. NHTSA complaints describe a sudden, forceful takeover of the steering wheel toward oncoming traffic, requiring the driver to fight the system. CarComplaints lists Lane Assist as the leading reported problem on the 2025 model year. The behavior appears tied to camera misinterpretation of lane markings - faded lines, tar seams, construction striping, shadows and crest transitions - compounded by camera calibration that was never performed or was performed incorrectly after a windshield replacement.

GM TSB 19-NA-076, revised February 2023, lists the 2022 Chevrolet Bolt EUV among the affected vehicles. On shifting into Reverse the center display shows either a blue screen with a 'Service Rear Vision System' message or a black screen with a red triangle and a crossed-out camera icon, with no rearward image at all. The condition can persist for an entire power cycle and typically clears only after the A11 radio enters and exits a sleep cycle. GM attributes it to software anomalies in the Video Processing Module or the rear camera, not to a wiring failure. Because FMVSS 111 requires a rearview image, a car that intermittently shows no reverse camera is a real safety defect and not just an annoyance. On EUVs equipped with the standard rear view camera (RPO UVB) the radio stores history DTC B395A with symptom bytes 08, 72 and 3A.