check engine light

[jayagha]

Check engine light on my 1994 e320 convertible came on again after being reset by a mechanic who claims the car needs a new wiring harnes setting me back $1000.00
Not sure he knows his staff,I know there are a no of reason for the light to come on so I was wndring ig anyone has had a similar issue and how it was taken care of.Spending a $1000.00 does not seem to be an option at the moment.
Thank YOu all for your help and feedback
Jay

[david s poole]

i think that he knows his stuff and you better hope that the electronic accelerator wiring is still good.

[skiier3_9]

The wiring harness on that car (all 93 - 95 MBs) is very prone to failure - do a search here, there are plenty of threads.

You could ask him what codes were retrieved or retrieve them yourself using the push-button/LED combo on the diagnostic module.

[Larry Delor]

I'm going through the bad wiring nightmare right now. Hope you get lucky with yours!

As skiier wrote, see if he will tell you what the codes were. Depending on when your car was made, you may be able to get the base codes yourself by counting LED flashes.

[Texholdem]

Hi,

since this morning my Check Engine light is on when headlights are turned on (low beam / high beam), the warning light goes off again when I turn off the headlights. I cannot figure out why turning on/off the headlights has something to do with "Check Engine". I'd appreciate all suggestions, thanks!

[david s poole]

sounds like someone has had the instrument panel out and the bulb for the light bulb out light is plugged into the check engine light hole.why don't you check and see if you have one of the small bulbs out when the lights are on.fix it and see if the light goes out.

[Texholdem]

Hi David,

yesterday I just managed to remove the instrument cluster, and you were right about the bulbs being switched.

Thanks for the tip.

[Texholdem]

My story about dash board warning light:
I bought my car 4 months ago with the Exterior light failure on, I thought no big problem but spent almost 4 months looking for the cause of the warning. All exterior lights were OK, no corrosion at sockets or so. I gave up then and accepted as a minor nuissance.

Then after a signal light was defective, the Check Engine light went off when headlight was turned on. After fixing the light CEL went away but Exterior light failure waring was still there. I posted my question here and as David correctly pointed out, the bulbs for Exterior light failure and CEL were switched. That means I have been driving with CEL on the whole time without knowing.

It turned out to be the Coolant temperature sensor was defective. I fixed the problem including switching back the warning bulbs and have the CEL no more but now I am not sure whether the seller had intentionally switched the bulbs to cover the CEL warning.

My experience for the next purchase is Be suspecting of any warning light on the dash board.

[stevebfl]

Whether you need a harness or not is not an ambiguous question. It is matter of fact or not. I would not consider diagnosing a car with the wiring harness problem and a owner not fixing one is asking for a boatload of trouble.

[Larry Delor]

Once you do a search for wiring harness posts, you will discover that most people say to open up a section of harness, and examine the wires closely. If you spot insulation that is cracked or worse, you will need to replace the harness. As a matter of fact, you will need to replace it yesterday, before it damages any components. Also, if the harness has the defective insulation, you will also want to seriously consider coming to grips with the fact that you will probably have to replace the ETA as well.

Shop around - Phil can get you a good price on a harness.

ETA= Electronic Throttle Actuator (aka throttle body)

Don't bother telling Benz that this is a safety issue and ought the be covered under some sort of recall - they will tell you they know nothing about it.