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1998 SL500, Panoramic Roof, Factory Xenons, Black/Black/Black 2012 GLK350 Black/Beige
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126 Posts
Discussion Starter #1
I've searched the BAS/ESP threads and cannot find my issue, so I am asking for assistance or a point to the thread I undoubtedly missed.

I have a '98 SL 500, 111K miles, which I purchased in June. Occasionally, when the car has been driven several miles, is fully warmed up and at idle, the BAS/ESP light will come on and the idle will increase to 1,500. The engine is then in limp home mode. I can turn the car off, restart it and the problem goes away. I have never had it do this with the engine cold. The ABS light does not come on, and I don't have any codes. I do have a strong battery - it is at 12.0 V with the engine off, and 13.9 V at idle.

Any ideas where I should start looking? I do have a CarSoft 7.4 multiplexer with the 38 pin connector and couldn't find anything with it.

Thanks
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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11,108 Posts
If your Carsoft communicating with the BAS/ESP controller OK ? (is it returning 'no code' or just not answering ?)
Since the BAS/ESP are speed related and you are getting the light at idle (car not moving) could it be the wheel speed sensors are messed up ?
 

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97SL500R129, 01ML320W163, 94E320W124 & 93500EW124
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2,921 Posts
I had the same BAS/ESP light-on problem on an ML320 and the culprit was the brake light switch. I don't know if this applies on an SL. But, the brake light switch is just $15 from the dealer. It may be worth to try (test) it first before replacing more expensive parts.
 

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1998 SL500, Panoramic Roof, Factory Xenons, Black/Black/Black 2012 GLK350 Black/Beige
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126 Posts
Discussion Starter #4
I reran CarSoft 7.4 and got the following from the BAS with the ignition on, engine not running. Looks like CarSoft can communicate with the BAS module, but not with the sensors and switches attached????

Any input appreciated:
---------------------------------------------------------
Single diagnosis BAS - Status: ERROR !

Module Info : BAS!
Module : BAS
MB - Nr. : 0 25 545 48 32
Supplier : Temic
Hardware-Version : 01/98
Software-Version : 01/98
Diagnosis recogn. : 0/02

bas_feh.dxt
C1025 CAN - Communication.

-> Verify the CAN - communication :
- Complete CAN - communication-
- The traction control unit
- CAN - Signal : Break light switch
- CAN - Signal : Wheel RPM

- Single diagnosis completed !
---------------------------------------------------------------
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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11,108 Posts
Well Carsoft indicated it was communicating with the BAS module and it (the BAS) has problem with CAN signal from the Brake light switch and the wheel speed sensor. So those 2 are the things you need to look at.

So clean or adjust (the mounting) or replace them.
 

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SL55, 300SE, GL450, Daytona 955i
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10,293 Posts
replace the brake switch at the pedal, clear the other code and see if the problems is solved permenantly...

if not, try cleanning VSS's...

if not, replace the offending sensor...
 

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1998 SL500, Panoramic Roof, Factory Xenons, Black/Black/Black 2012 GLK350 Black/Beige
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126 Posts
Discussion Starter #7
RKH & bayhas - Thank you for the input. It is a big help as I learn CarSoft and MBs. Will work on it next week and let you know how it goes.
 
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