'96 E300D Check engine light... no codes!!! - PeachParts Mercedes-Benz Forum

landev · #1 06-28-2010, 08:30 PM

Well, after spending another wad on my 96 E300D (suspension and tires this time), I headed down the road to work to pay for the repair. The car now has 171K on it and seems to run fine, however the "check engine" light came on combined with the "engine electronics" on the display. "No sweat", I'm thinking... nothing I cant fix with a code scan and (hopefully) a sensor swap.

I got the car home (seems to run just fine) and put my code scanner on it only to find no codes displayed. I tried to turn off the light with the erase function on the scanner, but no go on that. I'm not sure where to begin on this. I should mention the conditions... dry, 90 degrees F, AC running (fine).

Any ideas on this would be much appreciated.

Thanks in advance!

-l-

Jeremy5848 · #2 06-28-2010, 08:57 PM

Sometimes problems of this sort will clear themselves after the car has been re-started a few times. Keep driving the car and see if it doesn't go away (the light, I mean, not the car) after awhile.

TMAllison · #3 06-29-2010, 12:29 AM

I'd have to agree with Jeremy. There are a double handfull of codes that will reset themselves after 3 hot cold run cylces of they dont reaccur.

If it comes back, try to "plug in" on the go and scan it and see what pops up.

landev · #4 06-29-2010, 10:56 AM

Thanks Jeremy and Terry! I'll give that a go. I wimped out today and drove my 84 to work (it needs some exercise anyway.) I'll let you know what I find out.

Thanks again!

-l-

landev · #5 07-07-2010, 01:12 PM

Gents,

Seems that you were correct... the error corrected itself after 5 trips. I stopped by an autoparts store shortly before the light went out and tried their scanner. It showed a throttle position sensor error, whereas my scanner showed squat. I guess that's what I get for using my "Harbor Freight $40 special". I'm assuming that, should the error crop up again that this is a sensor replacement issue rather than an adjustment issue.

Thanks much for your help on this!

-l-

Matt L · #6 07-07-2010, 08:13 PM

I'm surprised that there was no code. TPS error is clearly not the problem.

The most likely code that you'll get is for the glow plug circuit. You can elicit that code any time you like, by cranking the engine before the plugs get hot.

pimpernell · #7 07-08-2010, 09:09 AM

Quote:

Originally Posted by landev

Gents,

Seems that you were correct... the error corrected itself after 5 trips. I stopped by an autoparts store shortly before the light went out and tried their scanner. It showed a throttle position sensor error, whereas my scanner showed squat. I guess that's what I get for using my "Harbor Freight $40 special". I'm assuming that, should the error crop up again that this is a sensor replacement issue rather than an adjustment issue.

Thanks much for your help on this!

-l-

Before changing out the sensors, I would use electrical contact cleaner on the the sensor connections. The "throttle position sensor error code" takes in about 4 or five sensors. Two are located on the side of the air filter box, and are the same part number. Also included is a small sensor connected to the intake manifold by a small black rubber hose, and then there is the actual "Throttle" connections that should also be cleaned. You should also check any of the vacuum hoses that come off the sensors for small leaks. I had the same code come up on my vehicle, and after cleaning all the connections, it has not reappeared. Good luck!!

landev · #8 07-11-2010, 12:48 PM

Matt, in the past, my code scanner was able to find problems in the glow plug circuit (at least it let me know I had a failed plug once-upon-a-time) so I'm not sure that is/was the source of the error... dunno...

P, Thanks for the info on the sensor snafu... as of yet, the check engine light hasn't made a return appearance, but if it does I will check connections. I don't suppose there is a resistance schedule for the various sensors?

-l-