New to MB and the forum, ASR light on, in limp home mode.

[turboswede]

My wife's 1995 E320T ASR light came on while she was backing up a steep hill in the rain, went into limp home mode, shut it off, restarted, all okay. Two hours later, ASR light back on, will not come out of limp home mode. Having difficult time finding code reading info on this car. Any help would be appreciated. Thanks in advance.

[mbdoc]

You need a scanner that can read codes from the electronic accelerator computer! That is pin 14 on the 16 pin diagnostic connector.

[Peter Guenther]

Sometimes it is a bad brake light switch, fooling the system into thinking you are braking.

[deanyel]

It's possible you can get out of the limp home mode, temporarily anyway, by clearing the fault code at the LED button on the 16 pin connector. With the ignition on, hold down the button for 3 seconds, count the number of flashes, then hold down button for 10 seconds, turn ignition off, repeat for other codes.

[Arthur Dalton]

Originally Posted by deanyel

It's possible you can get out of the limp home mode, temporarily anyway, by clearing the fault code at the LED button on the 16 pin connector. With the ignition on, hold down the button for 3 seconds, count the number of flashes, then hold down button for 10 seconds, turn ignition off, repeat for other codes.

Not quite ..
The button on the 16 pin connector is for CE lamp emmissions related codes only. That led/sw will not get you to the EA/CC modules..
As stated in an earlier post, you have to have a led tool and go to pin 14 .
And the count on that ECU is 2/3 sec retrieve and 8 sec clear..

[deanyel]

I could have sworn that I have on occasion gotten out of the limp home mode from the LED button only. I've always held the button down a little longer to clear as it seems to be far more forgiving on the long side.

[Arthur Dalton]

That would be a new one to me . Although there are some EA codes that will trickle ove to N59 module if the mapping does deem the fault to also effect Emmissions.
But even then, the actual ASR fault would be recognized by the EA/CC module, so I do not see how the ASR fault could be cleared from N59 Emmissions module, as the fault is still in the EA module to begin with.
.. but it may be possible, if the ASR was accompanied with a CE lamp activation

?????????

[deanyel]

It was - but I'm not sure about this - may be imagining it. In any case as you said he should be able to get rid of the limp home mode with the home made code tester.

[Arthur Dalton]

<>


Yes.. with the added benefit of being able to get direct module fault codes .

[turboswede]

I am finding conflicting info on which scanner will work with this car. MB cars are indeed unique in the automotive world, but this isn't a space shuttle, its not even OBDII. I've built testers for several other Euro and American cars. If I could find out which connectors, and what sequence the self diagnostics is looking for, I'm there. Can I test the ASR controller at the X11/4 connector?

[Arthur Dalton]

Simple led.sw tool is all you need on that chassis
ASR codes will be in EA/CC module [ pin14]

E320 16 PIN DTC Charts inc. pin 8, pin 14

[turboswede]

Okay, am I correct in thinking that pin 14 would be the negative side of the LED, or are you simply grounding pin 14 to initiate the test? How do you initiate the code sequence, is that w/ign on, engine off, press button for 3 seconds? What is the difference between the LED tester and the on-board LED? Any help would be appreciated, this info is not easily found on the factory tech CD's. If it's there, I haven't found it yet. These CD's have alot of great info, but they would only be more difficult to use if they were in German and written backwards. Thanks in advance.

[Arthur Dalton]

<>

No code info on CD.. very surprising, but they do have great schematics..

Anyway..on the led tool ..I just made a copycat version of the built-in led/sw circuit , so , the code retrieve/clear is the same as the built-in one .
With the tool , the plugs are color coded and on your chassis the bk goes to #1, Rd to # 16 and the odd color goes to the socket that is designated to the module you want to check.
In your case , you want access to EA/CC/ISC module , as that is where you will find ASR related codes .. that will be #14. I would also go to pin #8 , HFM module too, as that will show a possible code combo with the EA for better diagnosis..

[turboswede]

Thanks for the reply. I'll check the schematic to see how the on-board one is wired. Also, I can clear the code and it works fine for a few days although the last time it also turned on the check engine light.

[Arthur Dalton]

Originally Posted by turboswede

Thanks for the reply. I'll check the schematic to see how the on-board one is wired. Also, I can clear the code and it works fine for a few days although the last time it also turned on the check engine light.

The shematic is the same ..
The sw completes the led circuit and starts the code initiation to the module . The mod then sends back the flash to the neg side of the led through the designated pin /connector

http://members.aol.com/ajdalton7/ledtool.jpg