I have a 1999 STS and I am getting Speed limited to 90mph and Service Suspension. I called Cadillac and they want $150 just to look at it. So figured I would try here first to see if any one has some ideas of things to check to see if I can fit it.

The guy I got it from said it may be the ride height sensor on the air ride. Any ideas?

 

there is a code in the system u need to pull it out
more then likely there is a resistor at the bottom of the steering column causing it.

but pull codes there is a section on here that tells u how to do it

 

This what I got it narrowed down to so far. Any more help would be super!

C1252 - a problem with either the left front strut or its electrical connector.
U1255 - Voltage or data transmission fault.
C1711 - Goes with C1252 - RSS (Road Sensing Suspension). Something is wrong with the strut control circuit.
C1738 - The ELC (rear shock Electronic Level Control) compressor solenoid exhaust assembly has a fault. Up in the RR wheel well liner.
C1783 - Chassis Control system - this is a new one on me.

 

first of all u need to clear the codes all of them
drive it again
and check which codes r coming back
look at all connectors make sure they r in place and wire r not broken or shorted to one another or to frame
do u have access to a scanner with live data

 

Yea I did that already same codes.

I am going to put it up on stands this weekend. Was just trying to get ideas of things to look for.

So far the struts I found to check all the fuses, check the connections at the strut and the wires best I can.

The compressor solenoid exhaust assembly I am not sure how to actual check yet or even what it may look like I still need to figure that out.

The C1783 - Chassis Control system I have no idea what that could be. LoL

 

DTC C1783 ICCS2 DL Left Output Short CKT to GND

 

I got the exact same problem after my steering rack had to be replaced (dreaded castings breaking,...cannot understand why or why GM put such a poorly made rack on such a car,...but that's another story).

It was nothing to do with any resistors, the shop had not connected part of the front suspension sensor circuit. Have you had any work done on the front of the car anywhere? There are several sensor circuits that you need to check if you have, or if you have not had any work done get that issue GMTECH's advised of in their last message.