It has the dreaded ASR Limphome problem. The PO replaced the wire harness and then got frustrated with the ASR issue.

I've only had it for a day and haven't driven it, but it seems like the ASR comes on as soon as the car moves i.e. put the car in gear and the ASR light comes on. Sometimes immediately after starting it, the ASR light comes on.

I know how to defeat the ASR, but since I'll be driving this car in the Wintertime, I'd prefer to keep the ASR functional.

Are there any diagnostic procedures to figure out what the problem is? Anyone else have the ASR problem, what did you do to correct it?

Mileage 100684

Thanks

Marty

Had the light go on one time, and it turned out to be a defective brake light switch.
Let's hope your trouble is as easy (and 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

larry is right should be brake light switch but........buy from dealer a/market ones are junk.david poole dallas tx.

WEll I think that I have confirmed that the ASR comes on when the car is put in gear. Apparantly it sometimes 'sticks' in memory and turns on immediately. I disconnected the battery and when I reconnected it, I let the car idle for 3-4 minutes, no ASR, then as soon as I put the car into gear (R) the ASR light came on. I also noticed that revving up the car in park causes teh ASR light to come on. hadn't happened the first rev, but maybe the 3rd or 4th.

Brake light switch? Wouldn't just pressing on the brake to move the gear selector the cause the light to come on?

Marty

there are two circuits in the switch and one of them is open. david poole

If you know how to defeat ASR please tell us. I've searched these archives for hours, or maybe it was days, and came to the conclusion that it wasn't possible - just too many components involved.

To defeat ASR simply disconnect pins 25 35 and 37 on the ASR module.

I did this and the car's idle increased to 1200-1500 RPM while in park, but no surging of idle like when ASR is on.

If you need help locating the ASR module, ask.

What I'm trying to do is figure out if the 1500RPM is OK, or did I do something wrong. Also, I didn;t notice any change in performance between ASR defeated, and ASR on.

Does the 400e get really sluggish when the ASR light is on? I've only driven the car a couple hundred feet, as I still don't have tags on it.

Marty

I've seen ASR light with and without limp home mode. I actually sold mine - but there's so many nice cars out there for sale with ASR - that I won't touch unless/until there's a proven means of disable. I wouldn't consider 1500 rpms an viable tradeoff.

I tend to agree with you about the 1500 RPMs in park, but in "D" the RPMs are more in line around 700 I believe. I need to get tags on it and drive it some, but my limited experience with this car I don't think it's limp home mode even though teh ASR light is on.

Tomorrow I will know as I plan on getting it tagged and driven a bit.

Marty

I tagged my 400e and drove it to the post office to deliver Mercedes parts. The ASR light was on the whole way, but man this car has alot of power. No limp home mode to the post office. I turned the car off, went in when I came back out, ASR light turned on and the car was in limp home mode. WHAT A DIFFERENCE, coughing and sputtering. I thgen turned the car off and restarted her. A little coughing and sputtering, then NO limphome all the way home. But I was afraid to use the acceleration to make a left turn into oncoming traffic, all I need is for coughing and sputtering as cars approach me at 35 MPH.

I guess my next step is to defeat the ASR and see how she runs.

Marty

I like my ASR. I can stomp on the gas during a heavy rain, and make it across the road without spinning my tires and getting nowhere, or worse yet, getting only into the middle of the intersection instead of across it.


You wanna do donuts on someones lawn? push the snowchain button...it'll letcha.

__________________
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

Well I defeated the ASR (I know that I defeated it becasue the snowchain light illuminates when teh ASR is defeated), the car ran great going to UPS to drop off a cylinder head, she ran great going to Walmart (to pick up a wiper), but then on the way home from walmart, on the freeway (first time on the freeway for me in this car) she would hesitate and surge while at moderate throttle, she was fine under heavy acceleration, and fine when coasting, but inbetween I'd get hesitation then surges.

The PO told me he had the wiring harness replaced, and EA Unit R/R'd at Benntech or something like that in NC. but I didn't see the receipt, but he had no reason to lie to me, trust me he didn't.

Well anyway, the car idle's fine, smooth, at 650 (or so) when ASR is not defeated. When ASR is defeated (by interrupting pins 25, 35, and 37 on the ASR module) the idle RPM (in park) is 1200-1500. The idle goes down to about 600 when in gear.

Since I've defeated the ASR, the car has not coughed and sputtered like it did leaving the post office (see earlier post).

It does seem that I must depress the throttle a little excessive to get the car moving (both ASR on and off). If accellerating lightly, the car seems to shift late. When accelerating with a leadfoot, I get whiplash when the car tackes off.

The ASR it seems never turned on when the car is just idleing, but revving it up tends to increase the voltage across the ASR light, i.e. ASR light on.

So something is not right with the car, so I'm gonna build a DTC code scanner and see what I can come up with.

Anyone got any ideas, suggestions, or relevent symptoms?

Marty

Well I built me a DTC code scanner, very easy it is to make. I pulled codes

Pin 4 - LH-SFI NFF
Pin 8 - Base Module NFF
Pin 17 - Distributor Ignition NFF
Pin 7 - Cruise Control/Idle Speed Control
(Now the dtc code guide states a 16 pin data link connector, well I only have the 38 pin so I went with that on this test)
3 --- Right EA/CC/ISC actuator (left cylinder bank) (M16/1)
6 --- Starter Lock-out/backup lamp switch
Pin 6 - Anti-Lock Brakes
30 --- CAN data line to electronic accelerator/cruise control/idle speed control module
Pin 16 - A/C NFF
Pin 30 - SRS
3 --- Driver Airbag squib
4 --- Front passenger airbag squib
8 --- Voltage supply interrupted

After reading the code I deleted it.

I then started the car and revved up the engine a few times, and rechecked the codes,,, nothing new

Mileage 100704

Now time for a test drive. Remember my ASR has been defeated, I'm trying to seperate the pre ASR (sensors) from the Post ASR (Controls)

Will be back in a few.

mileage 100714

Marty

OK I'm back from the test drive and I've re-read the codes, I still have:

3 --- Cruise Control/Idle Speed control module (But that's from the diagnostic sheet for a 400e w/o ASR,,, I gotta find a sheet With ASR.

Right EA/CC/ISC actuator (left cylinder bank) (M16/1)

30 --- CAN data line to electronic accelerator/cruise control/idle speed control module

OH and the cruise control doesn't work. The car is not as responsive to the accelerator pedal (learned that word from the diesel forum,,, anyone driving a diesel and call it a gas pedal will, well, basically get flamed ), what i mean is the amount of pedal movement (0-20%) until the car moves is a little more then I would think, but then the next (20-40%) the car abruptly takes off. (40-100% HOLD ON to your hats)

All the other codes from my previous post have not yet re-appeared, so it looks like I gotta find the cruise control and the CAN, but I thought only Fords had a CAN

Anyone got any ideas about what to look for,,, or am I out on a limb by myself on this one.

Marty

I don't know why you don't look at your throttle actuator. ASR is part of the throttle actuator function, I believe.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".