steverino

After changing the plugs myself in my '02 C230K, the Check Engine Light came on and it ran rough. I learned that I was given the wrong gap for the plugs and when I corrected the gap the car ran smooth, but the CEL light remains on. I took it to Advance Auto for a free code reading and the car wouldn't talk to the reader. It showed an ERROR message as did the next reader I tried.

Also, three months ago, the CEL light came on and the dealer also couldn't pull the code then during the $50 diagnostic but for an extra $150 they were able to tell me that the fuel pump relay was bad which prevented the computer from communicating with the reader. Could the same thing be happening, but caused by a sloppy spark plug change?

Thanks for any help. This site has been great.

Stephen

BC-MB

I don't even own a MB but my experience with Nissans has taught me that if you simply unplug your battery overnight it usually gives the ECU time to reset itself, and just like magic the next morning when you plug your battery back in the light should be turned off. If your light is still on it's probably something worth getting checked out by a tech. Hope this works for you....GOOD LUCK!

SeaCoupe

Have you inspected the condition of your car's OBD Port?

Are all the pins aligned and in place? If yes, try cleaning the pins with some Radio Shack electric contact cleaner.

I can't imagine the car's OBD Port not running. If still no go, start checking fuses/ground for the port

E

Tangerine

Is the ODB reader up to date?

What happens and what you do after you plug back the battery terminal in a Mercedes, not Nissan is a hassle.

bwco

By unplugging your battery, you'll lose important data if your car is really running wrong. By the time the next cel came on, you may have already ruin some part of the engine. Some CEL may take a few check cycle for it come back on to tell u that it's wrong. A few check cycle could be as easy as 2 trips of hard acceleration to 100 km/h, stay there for 10 seconds, deceleration to 80 km/h and stay there for another 5 seconds, and go back up to 100 km/h. In two consecutive check cycle, then the CEL may come back on. So, don't unplug your battery just to erase your CEL temperory.

If you do wanna unplug your battery just to kill the CEL, you can simply unplug it, tap the brake a few times, then plug it back in. You don't have to wait overnight.

Cheers,
BWCO

amanonfire

I have tried 3 OBD readers and none have worked with my MB and 2 other MBs.

We need to make a list of OBD readers that do work.

steverino

I finally found a hand held reader at another Advance Auto that the guy there was able to use to pull a code. "P0410 Secondary Air Injection System Malfunction." The guy cleared it and it hasn't come back. It seems at least from this instance and from the forum member's above comment that certain OBD 2 readers may not read some Benzes so if at first you don't succeed, try try free again. This particular brand of reader was an Actron. The dealer would have charged me $50 for the same code pull so many thanks to Advance for providing this service for free.

And thanks to you guys for the advice.

Stephen

magnus203

I use a Bosch KTS550 for my reading and OBD diagnostics. Never had trouble connecting with an MB

magnus203

Glad to hear its all working fine now.

ohlord

item 94169 obd2 reads all mb and sae codes,clears,reads I/M status for smog testing and is usually on sale for 60 bucks.
if you have a hb near you they will price match the internet price if you take in a copy of the ad.
ohlord
always make sure to insert the plug into the obd2 port at the same angle as the port or you will get an iso protocol read error.