Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 09-26-2001, 11:32 AM
pmizell's Avatar
Benz Zealot
Join Date: Jun 2001
Location: Houston, Texas
Posts: 838
Check engine light -- 300E

Was driving along the other day when I smelled burnt plastic in the cabin. Looked under the car and found that a plastic bag has stuck to the cat converter and got fried; it eventually burned itself away.

Well, a day later the check engine light comes on when I'm at a stop, but disappears when I hit highway speed.

Any clues what's going on here?

Thanks for any replies!


'91 300E, 199k

Reply With Quote
Old 09-26-2001, 11:42 AM
Michael's Avatar
Join Date: Jul 1999
Location: Boston, USA
Posts: 2,700
O2 sensor is the only device that'll set off the "check engine" light. You can try running some Techron or other fuel system cleaner through, but likely you need to pop for a new O2 sensor.

Good luck!
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo
Reply With Quote
Old 09-26-2001, 01:17 PM
Registered User
Join Date: Aug 2001
Location: secret
Posts: 3,044
My local ******** tech told me that there are only three things that will light up the check engine light: the OVP, the O2 sensor and the coolant temperature sensor for the fuel injection. I changed all three and mine is STILL on and I'm not that fond of the color RED!
Reply With Quote
Old 09-26-2001, 02:24 PM
G-Benz's Avatar
Razorback Soccer Dad
Join Date: Apr 2001
Location: Dallas/Fort-Worth
Posts: 5,711
Just a guess, but...

...perhaps your idle mixture is too rich?

...catalytic converter is clogged?

...O2 sensor is picking up some chemical byproduct as a result of the plastic bag residue still burning on the cat?

Not sure whether those conditions will send a warning, but it's a thought...
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car
Reply With Quote
Old 09-26-2001, 02:39 PM
sixto's Avatar
smoke gets in your eyes
Join Date: Jun 2000
Location: SF Bay Area
Posts: 20,802
On a 91 300SE, there are maybe a dozen reasons for a check engine light. I got a check engine light for starting the car with the air temp sensor disconnected... or whatever that thing is at the snorkel of the air cleaner.

You can check the code behind the check engine light. Check the archives for the website that tells you how to check the code and how to erase the check engine light when you've fixed the problem. I went to the dealer and they were kind enough to check for me (no tools required). They were also kind enough to shield me from what they were doing.

91 300SE
81 300SD ... buy me
Reply With Quote
Old 09-26-2001, 05:27 PM
Registered User
Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,804
Check eng light is a heads up for Engine emmision management
system fault.
As last post states, there are several abdcode can be read to give the general area of fault.

Here are the codes that will trip light:
Reply With Quote
Old 09-26-2001, 06:31 PM
pmizell's Avatar
Benz Zealot
Join Date: Jun 2001
Location: Houston, Texas
Posts: 838
Thanks guys, I disconnected the - battery cable to reset the light, and it hasn't re-appeared since.

I cleared away any remnants of the burnt plastic on the catalytic converter, that I assume was causing the problem. It was maybe sending some bad air to the O2 sensor as a previous poster mentioned.

Thanks again!

Reply With Quote
Old 09-26-2001, 09:16 PM
Registered User
Join Date: Jun 1999
Location: Surrey, Beautiful British Columbia, Canada
Posts: 750
isn't it there is a corresponding message that can
be retrieved when the check engine light comes on?
Reply With Quote
Old 09-26-2001, 09:46 PM
pmizell's Avatar
Benz Zealot
Join Date: Jun 2001
Location: Houston, Texas
Posts: 838
Yeah Joel, the code can be retrieved and identified, but was hoping to avoid that cost by posting here. BTW, the check engine light came back on.

Anyone know what the ballpark is for getting the code for this check engine light problem? My guess would be the O2 sensor but wanna make sure before I spring for one.


Reply With Quote
Old 09-26-2001, 10:52 PM
Registered User
Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,804
If you are handy, you can make a tool to pull codes for $4
worth of parts from RS.
I contain the parts in a clear plastic film can so you are able to see the led. Use the removable top to mount the switch. Bring the test leads out a hole in the bottom.
Fits in your hand nicely.

Here is the wiring set-up.

Code retrieval is key on , hold button 2-3 sec., count flashes,
repeat step 1 to continue on to next.
To clear code , hold sw 8-10 sec. after each code .
No flash or 1 flash means no codes stored.
Disconnecting the bat to get rid of the ck eng lite serves you no purpose [ except temp putting the lite out] . You want the code to see why the lite came on.
There are pulse code retrivalinstructions better than these in the archive. Use search eng.
Or any ????? on the tool, you may email me.
Reply With Quote
Old 09-26-2001, 11:41 PM
Dirty Ern
Posts: n/a
My daughters 190E 2.6 (engine's probably close to the 300E) had a check engine light on, and the smog check guy found the tube that connects to the EGR valve was plugged. The tube is about 1/2" OD and goes from the valve around the back of the head and connects under the intake manifold. He disconnected the tube at the valve and started the engine and felt for vacuum on the tube, and there wasn't any. He took his air hose and gave the tube a couple of good blasts and the engine sputtered a bit and the tube was cleared, he cleared the code and the car passed the smog test. I'm sure the plastic bag wouldn't have anything to do with this scenario, but this might help Cap'n Carageous.

Reply With Quote
Old 09-27-2001, 08:58 AM
Registered User
Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,804
That is a common problem on these and SB has a good article
on that blockage w/pics. in the archives .

As one can see from your post, the mechanic got the code [ prob
egr ], found the problem in the egr system,, reset and cleared the code . Now it is fixed.
That is the procedure.
Not just turning off the lite.

Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
1988, 300E Engine shut down then Check Engine Light On oaouda Tech Help 0 02-15-2004 12:47 PM
'Check Engine' Light will not come on tr4me Tech Help 5 04-25-2003 10:57 AM
Check Engine Light M103 d2bernhard Tech Help 2 01-15-2003 02:37 PM
300e Check Engine Light w/Transmission in gear olivo880 Tech Help 2 09-06-2001 08:33 AM
intermittant check engine light 88 300E phunkler Tech Help 1 10-13-2000 07:55 AM

All times are GMT -4. The time now is 05:28 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page