Anyone have an idea what would cause the ASR to come on at start up leaving the car in LM? Once in a while it will start fine and after a few miles come on, the only other symtom is now in LM mode the check engine light is on. Any help will be greatly appreciated. Please don't tell me to search I have and haven't seen a post with this problem at start up. Thanks.

What is the "LM mode"? You might be OB (over-abbreviated) or PB (poorly abbreviated) here.

Its in the manuel, the car goes into LM mode and it drives like your pressing the brake and gas together.

I have a 1996 SL, so I have OBDII, but when my car went into limp it was due to a misfire, and the computer shuts down the engine except for a few cylinders. I have heard on the pre-OBDII cars that have the ASR light come on and go into limp it is usually the throttle control. As you know the throttle is not directly hooked up to the gas pedal, there is a little motor in there that moves the butterfly valve and this is how the computer can control the throttle position, idle, and acceleration to limit skidding and maintain control or traction. So it is either your EA (electronic accelerator) or a speed sensor, but with the engine going into limp it is likely the EA, however that model had the dreaded harness issue, has your harness been replaced? If not check it out and don't drive it until you are sure it is ok, the wiring insulation deteriorates and the wires arc, causing failures and can even fry the EA or engine control systems, costing way more than the harness itself. Don't mean to scare you, but better safe than sorry.
Check out our website for technical info on the 129 and the EA controls!
Best Regards,
Brian

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Brian W. Heitman

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