The Lyriq is electric, so a flickering MIL and a shaky standstill shudder usually trace back to the 12V system, battery management, or thermal faults.
Here’s what to check first, and when it’s no longer safe to keep driving.
First, a Quick Reality Check on the Lyriq
The Cadillac Lyriq is a fully electric SUV, so there's no gas engine to idle and no traditional "check engine" light. What you're actually seeing is the amber Malfunction Indicator Lamp (MIL) or the "Service Vehicle Soon" message, and that "rough idle" is really a shudder, vibration, or pulsing at a standstill — the EV equivalent of a lumpy idle. That distinction matters, because it points your diagnosis in a completely different direction than a gas car. A flickering warning light means the fault is intermittent and actively recurring, not a stored ghost code from months ago. Don't shrug it off: on an EV, a flickering MIL is often the first sign of a low-voltage problem that can escalate into a no-start or a derate on the highway.
