Cadillac Owners Forum banner

1 - 20 of 23 Posts

·
Registered
2000 Deville
Joined
·
19 Posts
Discussion Starter #1
Just started out of nowhere last week. Car has been perfect, but looked out in the street and the back end is jacked way up. Air shocks are fully inflated. The car looks ridiculous.

I pulled codes, and only the following two were set:
IRC U1016 Invalid or missing data for primary ID
RCC U1000 Invalid or missing data for primary ID

When I turn the ignition on, the compressor starts about 5 seconds later and runs for 60 seconds... Even though the shocks are fully inflated.

I popped the arm off the control arm on the left side and moved it all the way up and all the way down with the ignition on and nothing happened. No air venting and no compressor starting.

I think the problem is either the ride height sensor or the exhaust valve on the compressor. My question is: How do I test each component so I know what is malfunctioning?
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,785 Posts
When I turn the ignition on, the compressor starts about 5 seconds later and runs for 60 seconds... Even though the shocks are fully inflated.
That's a normal start up test run.

I think the problem is either the ride height sensor or the exhaust valve on the compressor.
Exhaust valve (or solenoid) would be my guess.
 

·
Registered
2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
Joined
·
26,323 Posts
Running for 60 seconds is not normal. After startup, it should only run for 5 seconds or so, then adjust further if necessary.
 

·
Registered
2000 Deville
Joined
·
19 Posts
Discussion Starter #4
That's a normal start up test run.


Exhaust valve (or solenoid) would be my guess.
I would have thought ride level sensor because no matter which direction I moved the arm, nothing happened. Wouldn't the compressor come on at one extreme and exhaust valve open at the other? By moving the arm, I couldn't make either action happen.
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,273 Posts
I would have thought ride level sensor because no matter which direction I moved the arm, nothing happened. Wouldn't the compressor come on at one extreme and exhaust valve open at the other? By moving the arm, I couldn't make either action happen.
==================================
Wouldn't the compressor come on at one extreme and exhaust valve open at the other?
yes -
pushing the rod UP simulates a low rear end -
and should fire up the compressor -

pulling the rod DOWN simulates a high rear end -
and should activate the exhaust solenoid -

check the ELC fuse and relay under the back seat -

------------------

the ride height sensor is completely sealed in epoxy -
I have never heard of a faulty sensor -

it is not uncommon for the exhaust solenoid to fail -
but - a fault code is usually set -
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,785 Posts
Running for 60 seconds is not normal. After startup, it should only run for 5 seconds or so, then adjust further if necessary.
:hide: Oops, I missed that. Yeah 60 seconds is waaay too long.

----------

I would have thought ride level sensor because no matter which direction I moved the arm, nothing happened. Wouldn't the compressor come on at one extreme and exhaust valve open at the other? By moving the arm, I couldn't make either action happen.
If the sensor/switch is at full extension, I suspect it would not activate the compressor. At least that would be my guess.
 

·
Registered
2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
Joined
·
26,323 Posts
If you allow the sensor arm to swing all the way up (it is spring loaded), it will set a code for a faulty sensor and the compressor won't turn on. Anywhere before all the way up should trigger the compressor.
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,273 Posts
If you allow the sensor arm to swing all the way up (it is spring loaded), it will set a code for a faulty sensor and the compressor won't turn on. Anywhere before all the way up should trigger the compressor.
=========================
(it is spring loaded)
no springs in the sensor -

I took one apart -

there is an inferred photo cell inside the box -
the lever is attached to a wheel - with a slot in it -
the slot allows or blocks the light -
 

·
Registered
2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
Joined
·
26,323 Posts
Must be an F45 thing then. All my sensors spring up when the pushrod is disconnected, and trigger a code and SERVICE SUSPENSION SYS message.
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,273 Posts
Must be an F45 thing then. All my sensors spring up when the pushrod is disconnected, and trigger a code and SERVICE SUSPENSION SYS message.
=======================
Must be an F45 thing then
that's possible
 

·
Registered
2000 Deville
Joined
·
19 Posts
Discussion Starter #11
cadillac1.jpg
cadillac2.jpg

This is how ridiculous my car looks.

I've checked the relay and fuse and both are OK. Does anyone have a procedure for testing the exhaust valve and load sensor? I really hate to just start changing parts.
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,273 Posts
View attachment 300705
View attachment 300713

This is how ridiculous my car looks.

I've checked the relay and fuse and both are OK. Does anyone have a procedure for testing the exhaust valve and load sensor? I really hate to just start changing parts.
=========================
I would simply remove the air line from one of the shocks -
let all the air out -
reattach the air line -
start the engine -
see what happens -
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,785 Posts
I popped the arm off the control arm on the left side and moved it all the way up and all the way down with the ignition on and nothing happened. No air venting and no compressor starting.
We know the compressor works, so this sounds like a bad sensor/switch.
 

·
Registered
2000 Deville
Joined
·
19 Posts
Discussion Starter #16
Submariner409. I've searched and can't find the posts. Maybe you could point me in the right direction with a link?
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,273 Posts
Submariner409. I've searched and can't find the posts. Maybe you could point me in the right direction with a link?
===========================
did you try removing one of the airlines
to deflate the shocks like I suggested?
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
68,479 Posts
Submariner409. I've searched and can't find the posts. Maybe you could point me in the right direction with a link?

This thread
had 15 posts prior to this one - suggestions range from solenoid control head to compressor to height sensors to air lines.

Which model Deville - base, Concours (? in 2001 ?), DHS, DTS ? It can make a difference in the level control configuration.

You could also surf through Tech Tips and Suspension. (Not trying to be difficult, but it's all in here somewhere.)
 

·
Registered
2000 Deville
Joined
·
19 Posts
Discussion Starter #19
Sorry... I've seen all the "could be's", "might be", "try this", and "try that" posts...

My question is very specific and I can't find a thread on it...

Does anyone have a procedure to test the load level sensor and the exhaust valve?

And, yes, I let the air out of the system be removing a line. It just pumped up to max again
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,273 Posts
Sorry... I've seen all the "could be's", "might be", "try this", and "try that" posts...

My question is very specific and I can't find a thread on it...

Does anyone have a procedure to test the load level sensor and the exhaust valve?

And, yes, I let the air out of the system be removing a line. It just pumped up to max again
------------------------------
Does anyone have a procedure to test the load level sensor and the exhaust valve?

YES - but it requires the TECH2 tool -
 
1 - 20 of 23 Posts
Top