mjcother

1998 SLK230, 82k miles, I have a check engine light (not sure how long it has been on, it hides behind the cruise control knob ;-)

Sometimes it feels like the fly-by-wire throttle is not opening as much as I am pressing down.... and a few times over the last 40k miles, it has hit the rev-limiter instead of shifting, so maybe the second code is really my problem... I did get fuel from a different place last time, I am going to fill up tomorrow from my normal place....

I had the codes read at autozone:

1: P0803 - upshift solenoid circuit malfunction
2: P0170 - Fuel trim malfunction (bank 1)
3: P0440 - Evaporative emissions control system malfunction



I did a search and only found the names of the codes at http://www.carsoftwares.com/mercedestroublecodes.html , which I already had from the scanner.

other cars call this a skip shift, or something like that, but I have never really noticed it ever skipping a gear.

If someone has the official manual on CD and can give me some pointers, it would be great... I would not mind spending money on a manual, I just want to know what I am getting for my money...

thanks,
mike c
Clearwater, FL

muscle4lew

you can down load the manual here......
http://www.oldweakandpathetic.com/slk/

do a search the instructions for burning on a CD is here also....

mbtech208

The fuel-trim code has little to do with what kind of gas you're using. It's most likely the fuel-trim is maxed out full-rich because of a bad mass-airflow sensor. The upshift problem is probably the electrical shift solenoid plate that sits on top of the valve body. That conductive plate seems to fail more often than the solenoids themselves. As far as the last code, early SLKs had numerous problems that would trip evap system codes. It could be a loose gas cap, leaking canister shut-off valve, leaking charcoal canister, leaky purge valve, fuel tank pressure sensor, or any/all of the above.

mjcother

Thanks to both of you for the helpful information...

#1
electrical shift solenoid plate on top of valve body..... sounds like tranny removal??? hmmmm I just had the tranny out and apart in my '00 jeep wrangler this weekend, but that was a manual tranny.... I think I will research the CD a little before I decide to tackle this myself....

#2
Sounds like from what I have been reading that I should just go ahead and put a new MAF sensor in becasue if it is not bad, it probably will be in the future??? (I did check for vacuum leaks with a can of brake cleaner and there was no indication of a leak)

#3 will tinker with the evap stuff in my spare time


-mike c
Clearwater, FL

mbtech208

The valve body is super easy to get out. Take the pan off, unplug the electrical connector, remove the 7mm bolt in the middle of the connector plug, take the plug out, then theres about 9 or 10 bolts holding the valve body in.