It could be a coincidence.

I had the same warning and it turned out to be purge valves AND a fuel pump that was not operating at full capacity.

Replaced both and code went, nothing to do with the gas cap in the end at all

 

I understand, except that my situation is different (I think). I had zero codes or issues prior to swapping fuel caps. Is this vehicle so finicky that just a simple swap of a fuel cap can lead to purge valves and fuel pump needing to be replaced?!

In either case, I might be able to make it in to the INDY for a scan. Thanks to all for the help/diagnosis.

Mike

 

Subbing to this, hope to hear back about your situation. Today my car showed a CEL, car seems to drive fine but planning to stop by my indy shop on monday for code scan. No gas cap swap in my case. Over the phone they suspected thermostat, we'll see. I'll report back as well, first "problem" with this car.

 

Well, INDY ran his scan tool and cleared the CEL. No real explanation/reasoning behind why this happened, but suggested that I drive the car a couple weeks to ensure CEL doesn't come back, and then maybe try the AMG fuel cap again.

Guess we'll see.

Mike

 

why didn't you just put the AMG gas cap on in front of your Indy? Start the car to get the check engine light and then let him clear it again and then confirm it's that new gas cap?

 

That's a good question, and honestly, I have no idea why I didn't.

I'm going to have to chalk this one up to idiocy.

Mike

 

Reporting back, my CEL did end up being the thermostat like my shop suspected. Apparently this has been extended covered by Mercedes, on my car at least until 2034. my shop actually had a G63 at the dealer for the same job so I left the car with them and it will go for replacement and I shouldn't have to pay anything.

 

Second follow up now that I have picked up my car. Kind of a strange story, my shop left my car with the dealer they use and even though it read the same thermostat code as the 21 G63 they also had there, the dealer's prescribed solution was not replacement like they did to the G63 but rather a software update of some sort. Car is back and no CEL but I will be keeping an eye incase it comes back.

 

Not that anyone reads the gas cap, but it warns you 'do not top off'

Old habits die hard