My cousin has a 2015 Chevy Malibu, and we're trying to figure out what to do next.
A few months ago, the car started having a bunch of strange electrical problems:
* "Service Power Steering" warning
* Power steering would suddenly stop working for a moment
* Dashboard lights and gauges would flicker
* Engine would sometimes shut off
* Door locks would randomly unlock and relock
* Multiple warning lights and transmission communication codes would appear
The transmission itself always shifted and drove normally, despite the transmission connection/communication code.
We eventually discovered that disabling the automatic stop/start system with an aftermarket bypass cord completely eliminated all of the problems. The car ran perfectly for about four months with the bypass installed.
Then today, the exact same electrical problems returned, even with the bypass cord still installed.
We've already ordered another bypass cord in case the first one has failed, but we're not convinced that's the actual root cause anymore.
Before all of this, we also had the steering control module replaced after a repair shop diagnosed it as the problem. The repair cost about $2,000, but the exact same symptoms came back just a few days later, so replacing that module clearly didn't solve the issue.
The battery and alternator have both been checked and were reported to be good.
We've also contacted a couple of auto electrical shops, but they told us this is the kind of problem that usually needs to be diagnosed by a Chevrolet dealer because it likely involves multiple control modules or the vehicle's communication network.
My questions are:
* Has anyone seen a 2015 Malibu do this before?
* Could the automatic stop/start system or one of its modules be causing these intermittent electrical failures?
* Could a loose ground, damaged wiring harness, or failing Body Control Module (BCM) cause all of these symptoms?
* Could this be a CAN bus communication issue rather than a bad steering component?
* Has anyone seen an aftermarket auto stop/start bypass work temporarily but eventually stop masking the underlying problem?
We're trying to decide whether it's worth taking it straight to the Chevy dealer at this point instead of continuing to replace parts.
Any advice from mechanics or anyone who's dealt with this issue would be greatly appreciated.