NHTSA complaint #11668979

Owner complaint summary

Hi, this vehicle is owned by Surreal Development LLC. A company whom reverse engineers vehicle. GM has an issue in their Cadillac Lyriq's which causes a complete failure of the vehicle's communication systems without warning while driving. This issue appears to affect all Global B vehicles but it is most severe in vehicles with one pedal driving (Sierra EV, Lyriq, Blazer EV, Optiq, Silverado EV, Equinox EV, etc...) The error is likely within the vehicle's Serial Data Gateway Control Module but it is unclear. The vehicle recovers from the communication quickly (within seconds) but it causes long term adverse affects for that driving period. 1. The vehicle will light up with warnings (Service Traction Control, disengage super cruise, disengage ACC, etc...) 2. The driver's pedal will go into safety mode. 3. A "Service High Voltage" system warning may or may not appear. The safety concern is mostly in #2. When this happens it is very jarring to the driver as it drastically changes how the vehicle responds. While the vehicle may state one pedal driving is disabled many times it still indicates it is on within the controls (likely due to an error in the compounded communication fault). This can lead to the driver rear ending the vehicle in front of them or rolling over. The fault does not correct itself until the vehicle resets (powers off/on). The issue is common and affects many owners of the Cadillac Lyriq. The only diagnostic data we see are communication faults across many modules.