THIS IS FOR A 1987 S4......

Why would you want to remove your LH brain?

Well, probably 3 reasons...1) it has failed or 2) your trouble shooting and need to swap one out.... or often forgotten 3) you are have some WELDING done on your car! ZZZZZZZZZZzzzzzzzzzzzappp!

When has a LH brain failed? That is a good question in that it can manifest itself in many ways. The only sure fire way to know is to swap one out with a car that is known to run fine. Ive seen brains fail abruptly with out warning.......turn key and injectors fire immediately before engine turns over, car will not start...... and I have seen them fail slowly over time, displaying very annoying, problematic symptoms that can drive you crazy trying to trouble shoot. The problems are there but the car still runs and starts..only to suprise you now and then : )

I have tested coils, cleaned rotors/caps, installed new plugs, swapped MAFs, clipped wires to the idle stabilzer...etc etc to only find that a LH BRAIN swap cured the problem.

If you have some very random, erratic engine gremlins it may be wise, if you have access to another, to swap LH brains out.


this is how you do it....

1) DISCONNECT THE BATTERY!!!!!!!!!!!!!!!!!!!!!!

2) locate the LH BRAIN...passenger footwell...behind a cover....right side...module on the right

3) Unlatch the retaining clamps. Even when loose the connector may be tough to pull out..... be careful when you pull the leads out. Dont force or bend the wire bundle anymore than you have to....odds are this wiring hasnt been touched in 14+years.

4) With the plugs removed and the wiring harness tucked out of the way, get an allen key and loosen the two bolts that hold the mounting bracket to the car.

5) Once these 2 bolts are removed the whole assembly should pull out....the EZK is still attatched to the bracket and will come out as well. On the front of the bracket you will see a fairly large pin that slides into a rubber grommet on the firewall. this helps center and anchor the bracket when it is in postion. With the unit out, remove the 4, 8mm bolts that secure the LH BRAIN to the bracket...once done the Brain will pull out! DONE!


Installation is a reverse process. When you hook the battery back up, the car will display some erratic idling and poor performance until the brain "figures things out"....

Need an replacement LH brain? THEY ARE GETTING VERY HARD TO FIND!! try www.928intl.com (928International)


Click the logo for an LH BRAIN from...