Two questions about computer testing
 

Today I received Carsoft 7.4 multiplexer.

I have two questions about 600SEL 1992 W140 diagnosis.

1. What is the system used in this car? (OBD-I, OBD2 or analog)?
2. I have three wires to connect 560SEL 1990 W126 car. How do I connect them to the car?

Thank you. :)

1. What is the system used in this car? (OBD-I, OBD2 or analog)?

Which system do you refer to? Engine management is OBDI, others are analog others digital. By analog I presume you mean impulse.


2. I have three wires to connect 560SEL 1990 W126 car. How do I connect them to the car?

The 126 car is only analog. The red wire is power the black is ground and the data is yellow, usually. The data must be placed into the proper test pin for the system in question.

You need nothing more than an LED in series with a 1K-ohm resistor to read codes on these early cars. My experience with a Carsoft non-"multiplexer" unit on a 1990 car was not good -- it could read codes from only a few systems. You may have better luck.

I have 8 ports in the 560SEL 1990. To which port I must connect the black and the red connectors?

The black goes to socket #1 of the diagnostic connector. The red lead goes to battery voltage; but there is no socket for it on the connector, so you'll have to use alligator clips or something to make a connection some place.

To make it easy, just use the battery terminals for the Red+ and Blk-, then you just use the third connector to the correct DM data pin.