lrizzi

Hi all:

I have a C300 2015.
About 6 months ago, the dash started to report "Malfunction - see operator manual" with a light bulb above it.
Looking around the car, I discovered that the problem is that both left and right backup lights don't come on.

First odd thing: this is the wrong message. The message "generic malfunction " should refer to the courtesy lights. A problem with backup lights has its own message, which is NOT displayed.

Of course the problem is intermittent: on for 3/4 days in a row (with lights not coming on), and then it disappears and the lights start working again.

I took it the to the dealer already and of course the problem didn't show up and they told me that if the code doesn't show while the car is there, there is nothing they can do to diagnose it.

Anybody has any idea of what can cause both left and right reverse lights to stop working intermittently with a wrong code on the dashboard?

MASSC450

Sounds like an update is needed or a loose connection somewhere. My old 2015 C300 Sport 4Matic needed a couple updates performed by the dealership for funky messages that would pop up sporadically...all under warranty.

Next time it happens, take a picture of the warning message/light to show to the service dept.

auditoamg

NO!!!!! This is lazy on the part of the service department, first of all. The codes are STORED in the systems (pending and prior) fault codes so that the dealer can see a history. Second, have you had your battery stress tested? I have a brand new car that had similar warning messages regarding various lights. It turns out, my dashcam was draining the battery and low voltage was causing funny mesages and behaviors. Even after the car was started... Just a thing to check.... ;-)