The workshop manual starts with "disconnect ASU electrical connect, followed by a CR(#)

For example... to test air pressure sensor signal circuit fault..... Disconnect ASU electrical connector, CR(#88) then Disconnect the valve block electrical connector, CR92. 3. Measure the voltage between CR92, pin 02 (G) and GROUND.
(Does this mean that I put the + end of multimeter on pin 02 of the valve block electrical connector and - end of the multimeter on any metal surface?)

I am pretty sure ASU = Automatic Suspension unit and the CR#88 is the air pressure sensor electrical connector, but I just want to be certain

Thanks guys, I have rarely done any electrical tests before so I want to make sure I am doing them correctly

 

Aloha hawaiianjag,

If you don't have the X350 Electrical Guide, you will need it to ensure that you measure at the correct connectors and pins. There are some pins you do not want to short to ground. If you don't have the Electrical Guide, send me your email address via private message and I'll email it to you.

The ASU is the Air Suspension Unit, also called the ASM (Air Suspension Module), ASCM (Air Suspension Control Module), or ASECU (Air Suspension Electronic Control Unit). The connectors on the ASM are numbered on the electrical schematics, and page 31 of the Electrical Guide (page 33 of the pdf document) shows the pin-outs of all five of the ASM's connectors. The black 9-pin connector at one end is CR88.

CR92 is the 3-pin connector on the pressure sensor on the valve block.

When measuring to ground, it is best to touch an actual ground stud if there is one nearby (if you have the rear seat out to access the ASM, there is a ground stud there - it would be a good idea to disconnect the battery negative cable and clean that ground stud while you're there). If you can't access a ground stud, you can usually find a good ground on a bare spot of metal on the body/chassis or engine.

Cheers,

Don

 

Thanks Don. You are the MAN!!! PM sent