LeSabre's Electrical Systems Fail After Service Visit

Had similar symptoms with my 2008 Buick Lucerne last month. The electrical problems started showing after routine maintenance, including unusual navigation failures and electrical glitches throughout the system. The root cause turned out to be a faulty immobilizer system that was accidentally activated during service. The diagnostic check revealed the transport mode was indeed left enabled, but that wasnt the main issue. The service technician found corrupted software in the main control module. It required a complete software update for the vehicle electronics system and reprogramming of the immobilizer. This was actually a serious issue that could have prevented engine start if left unaddressed. The fix involved: Full system diagnostic scan, Software reflashing of the main control module, Immobilizer system reset, Testing all electrical components This type of problem often appears simple but requires proper diagnostic equipment to identify. Would strongly suggest having it checked at a shop with current Buick diagnostic tools. These symptoms shouldnt be ignored as they can indicate deeper electrical system issues.

Thanks for sharing your experience. Your situation sounds almost identical to what happened with my LeSabre last year. After getting my key fob reprogrammed and updating the car configuration settings, most issues cleared up. But about a month later, the vehicle settings started acting up again until they found a faulty ground connection that was causing intermittent electrical problems. Do you remember roughly what the repair cost came to? Also, have you had any recurring issues since the software update and immobilizer reset?

The repairs were completely covered under warranty since my Lucerne was still new at the time. After the transport mode was deactivated, software updates installed, and the immobilizer system reset, everything has worked flawlessly. The diagnostic check confirmed all electrical systems are now functioning as designed. Unlike your situation with the ground connection issue, I havent experienced any recurring problems with the automotive electronics. The key fob and all vehicle systems have remained stable for 6 months now. The technician mentioned that keeping the vehicle software current helps prevent these kinds of electrical gremlins from popping up again. It sounds like your ground connection problem was a separate mechanical issue rather than the software-related concerns we both initially faced. Regular system checks can catch these issues early before they develop into bigger problems.

I finally got the problem resolved completely. After your suggestions, I took it back to the shop last week. The mechanic found that the car electronics were stuck in transport mode from the previous service. While fixing that, they also discovered that some car configuration settings had been reset to factory defaults. The full diagnostic scan showed my ground connection was still giving intermittent problems, so they replaced the entire wiring harness near that area. The total repair came to about €450, not cheap, but worth it to have everything working properly again. They also performed a software update on all modules while it was in the shop. No issues since then, the navigation works perfectly, all electrical systems are stable, and the vehicle settings have stayed exactly as I configured them. Really glad I got it sorted before winter. Thanks again for pointing me in the right direction with the transport mode possibility.