Hello, this is my first post, unfortunately its a troubled one. Yesterday we bought a 94 E420. Test drove the day before, and everything seemed fine through purchase. 5 miles down the road the check engine light came on. The gf neglected to mention this until after other problems started. 20 miles out the car stalled at a toll booth, after an hour of checking fuse and relays and deciding to send her off with the other vehicle and call a tow truck, i tried to start it one last time and it fired right up... i dont remember seeing the check engine light here but i could have missed it.

I drove the car a few blocks last night and it stalled in a parking lot, but started right back up. Im guessing this problem is just a bad crank sensor.

When i started it up the next time, the ASR light came on, it slammed into reverse, and i had no throttle response from the engine until half way down. This was accompanied by a very jerky throttle when depressed enough, the vrmvrmvrmvrm idle between 800 and 1200. I shut off the car for a bit and restarted, same symptoms but with a check engine light.

i checked the onboard diagnostics module. 17 flashes which i gather is code 17: Data exchange malfunction between individual control module.

soo.... help please!! I cant find any information about this code and I dont have an MB adaptor for my obdii scanner.

Its the gf's car and she's really upset and about to demand her money back. The previous owner is supposedly attempting to take care of the problem but he's not very prompt. He insists its been a great car and never had any of these problems. He's and old timer and after talking with him a lot I do believe him.

the first thing i would suspect on any 94, especially a communication error, is the engine harness and all the little harnesses. get the records from the po and see if ANY harnesses have been replaced. good luck, chuck.

I'd try to return it just because it has ASR. But to try to salvage it the first thing to do is build the code reader and read the codes on the 38 pin connector in the black box where the battery would be if it wasn't in the trunk. Try a search, check your private messages and this - http://www.k6jrf.com/MB_X11.html

thanks for info so far. I guess I'll work on an analog box. The diagnostic system on these cars is... ridiculous by my standards. Especially when i unscrewed that round cap with my obdii scanner in hand... looked in the hole and thought... oh ****.

i have a quick question tho. my e420 has the longer push button with led and pins up to #8. This is located right in front of the (F23??) box. Every pic or diagram ive seen here or on my Mitchell software shows a more squarish box with more pins by the back right corner of the computer box. is this normal for a 94?

Just found out she filled the tank with 87 octane... could this be causing some of the problems?

This is a state of the art diagnostic system for the era. Your "standards" must be for later cars - this is a pre-OBDII car. There is no normal for a 94 model - it varies by model. Your car has a 38 pin connector and an 8 pin connector. To get the full picture you need to build the 38 pin code reader and read the codes. 87 octane is not a good idea but you've got other problems.

I didnt mean to insult MB's pre obdii diagnostic logic. Im just used to obdii and this stuff is from a different book. ok so heres the detailed scan, i went out and built a "scanner" fun lil project.

N3/1
17

N30/1
21, 30

N4/1
clear

N16/1
6, 9, 10, 11, 12, 13

N59
17

N2/2
6, 8


I know the N16/1 codes 10-13 are a false reading, they're fuse codes and all those fuses are fine. and all but an A/C clutch and seatbelt switch code definately could be caused by a voltage problem. Looks to me like I should start by repairing the harness and checking grounds. Any other ideas?

I also noticed my oil pressure is pinned @ 3 bar all the time now

I agree with rebuilding the harnesses (if they need it) or you can buy new ones (not cheap). If the big harness is ok, then check the harness for the ETA and the ETA internals themselves (involves removal - see other threads about this).

Or, if possible, bring it back, unless you bought it really cheap.

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

$2500, it has 269000 miles tho, but I would NEVER believe that if I didnt have proof of the mileage, engine bay looks like a 20k mile car and previous owner never cleaned it. I'll dig in deep on the harness tomorrow. The paint has some scratches and flaws but no rust anywhere and the bottom side of this thing looks amazing. When test driving and examining i could even hear the crispness of the compression.

If you have the option you should take it back - not a good deal relative to the price of a non-ASR, lower miles car.

I'm still testing like crazy and the only failure I've seen yet is a voltage failure between pin 12 and 28 on the LH module (I think, I'm not home right now to check myself on that). I'm trying to figure out an easy way to get to the N59 for more tests. So far I have every indication to tell me all easily accessed wiring is good. I have a feeling ill be tearing into the EA soon but evidence points to a voltage issue.

New observation. I go into limp mode just a few minutes after startup, seems like when the car is just starting to warm up but long before stable temps are reached. Has anyone experienced this?

I've been trying to test the wiring between the connector for the electronic throttle (X1) and the connector for the EA module (N4/1) before I rip out the throttle and start repairs on it. Alldata's test procedures and wire diagram both show pin 2.12 of the N4/1 connector going to pin 9 on X1 and that this is a voltage supply for the throttle. pin 9 has no contacts on either male of female end of the connector. I also checked continuity on every single contact on X1, none of them make contact with pin 2.12.

I am completely lost and kind of upset that the diagram doesnt match the car at all.