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Registered
2004 DTS-Continuous Variable Road Sensing Suspension
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7 Posts
Discussion Starter #1
System is not functioning. Ride is very rough. No alerts from computer system.
Had rear shocks replaced (supposedly with proper units). Could it be that they installed wrong units, and blocking resistors to fool computer, or is there another possibility (bad air sensor?).
Please advise.

Thanks.
George M.
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,513 Posts
You'll have to do a visual inspection of the shocks to see if the body harness pigtail is actually plugged into each shock - along with the ELC air line. Check the link rods for the ELC height sensor(s).

Your car, from the side - at a distance - on a level parking lot, should appear level or with the slightest hint of forward rake.

Use the sticky thread - on the main Deville forum page - titled "How to pull codes" to learn how to enter the car's built-in code scanner/reader. Write down any found codes, return to the sticky to open the link to all OBD-II codes; decipher your codes and post it all here.

Welcome to CF !!!! :highfive:
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,286 Posts
Could it be that they installed wrong units,
and blocking resistors to fool computer,
sure - how much did you pay for the shocks?
ACDelco is the ONLY supplier of original F45 "active" shocks -

the part numbers are 580130 - LEFT - and 580131 - RIGHT -

the best - discounted - on-line price for EACH shock is around $500 -
retail price is $933.66 - EACH -

so - if the parts used were NOT the genuine AC Delco parts I listed -
and/or you paid less than $1200+ plus labor -
chances are you did NOT get the correct "active" shocks -
 

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Registered
2004 DTS-Continuous Variable Road Sensing Suspension
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7 Posts
Discussion Starter #4
The shocks do re-level when weight is loaded in the trunk, which would appear to show that the load leveling is working.
Does the continuous sensing aspect operate in a different manner? Could there be a bad sensor for that system, independent of the load leveling operation?
Any input is greatly appreciated.
GMarrino
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,513 Posts
ELC (Electronic Level Control) and CVRSS are two entirely different critters. ELC compensates for extra loads in the trunk or back seat. CVRSS is the sophisticated active suspension controls system.

CVRSS uses sensor inputs for engine and transmission speed/power, wheel speeds, braking level, body roll, pitch and yaw, acceleration, deceleration, desired turn radius and actual turn radius, degrees of steering wheel rotation, plus more - to control body attitude and handling under all conditions by rapidly changing strut and shock internal fluid orifice size as maneuvering demands become greater or less.

Complete diagnostic trees for suspension faults are in the GM/Helm service manuals.

It's a very sophisticated system and is not cheap to maintain, which is why many Cadillac owners of these used cars elect to replace worn components with cheap passive parts, thus giving up the suspension controls systems. As posted, if you paid a low price for rear shock replacement, you did not get the CVRSS units. Look in www.rockauto.com for your suspension parts.

EDIT: To verify ELC, turn the key on - the compressor should do a preload and prove-out after about 6 seconds. Pop the trunk. Leave the key on and you and 2 assistants sit on the open trunk lip. Does the compressor run and level the car ?? OK - all hop off and you listen in the RR wheelwell for escaping air as the car levels again. OK ?? Good to go for ELC.
 

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Registered
2004 DTS-Continuous Variable Road Sensing Suspension
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7 Posts
Discussion Starter #6
ELC works just fine. Does this prove that the shocks are correct, or can they still be wrong? Does the ELC operate separately from the CVRSS system or are they tied in together? - Cannot find a diagram.
Awaiting an inspection regarding all other issues (elec connections/codes/etc.).
Thanks,
Gmarrino
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,513 Posts
ALL these Seville/Deville/Eldorado models - and many other Cadillac models - uses ELC. It is for rear height control and the suspension operation, passive or active, is not tied to it.

RSS, CVRSS and MRC are the active suspension control systems, used only in the upscale performance models above base. The FWD base models - SLS, Deville, most DHS, ESC, couple others - use strictly passive "Cadillac ride" marshmallow suspensions. A new, tight passive suspension is quite impressive in these cars, but "new" was last seen in 2004 unless a fanatic current owner has replaced every possible piece and bushing in the suspension system.
 

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Registered
2004 DTS-Continuous Variable Road Sensing Suspension
Joined
·
7 Posts
Discussion Starter #8
ELC works just fine. Does this prove that the shocks are correct, or can they still be wrong? Does the ELC operate separately from the CVRSS system or are they tied in together? - Cannot find a diagram.
Awaiting an inspection regarding all other issues (elec connections/codes/etc.).
Thanks,
Gmarrino
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,286 Posts
ELC works just fine. Does this prove that the shocks are correct, or can they still be wrong? Does the ELC operate separately from the CVRSS system or are they tied in together? - Cannot find a diagram.
Awaiting an inspection regarding all other issues (elec connections/codes/etc.).
Thanks,
Gmarrino
=================================
ELC works just fine.
Does this prove that the shocks are correct,
or can they still be wrong?

due to the ridiculous cost of replacement CVRSS struts and shocks -
many - if not most -
decide to replace ACTIVE units with the much cheaper PASSIVE units -

this doesn't make them "wrong" -

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

Does the ELC operate separately from the CVRSS system
YES - two entirely different systems -

ELC - Electronic Level Control - uses rear shock absorbers that have built-in air bladders -
these bladders can be inflated -
by the built-in air compressor -
to raise the rear of the car -
to compensate for additional weight in the back seat and/or trunk -

ALL Deville - Seville - and Eldorado have ELC systems -

CVRSS - Constantly Variable Road Sensing Suspension -
or F45 - or simply put "ACTIVE" suspension -
is/was available on certain models of Deville - Seville and Eldorado -

CVRSS - as the name imply - constantly changes how stiff -
the front struts and rear shocks ride -
depending on all the input from various sensors through the car -

the "PASSIVE" struts and shocks have a "fixed" valve -
so they always react the same way -
regardless of speed - cornering - breaking - accelerating - etc -

the ACTIVE units are independently controlled -

for example - on a hard - accelerating - left turn -

the right side front strut becomes "rock hard" -
the right side rear shock become very firm -
the left strut and shock remain somewhat soft -
this is to reduce body roll - and increase handling -

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

unless you drive "on the edge" -
you will never notice the difference
between active and passive suspension -

an example of $avings potential -
as stated before -
the best price on-line for your rear active shocks is $500+ EACH -

compare that to the passive Monroe MA822 - $65 - for the PAIR -

then ask yourself -
how bad do you need the active units?
 
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