05 STS broken suspension ride height sensor

[kevm14]

I've been hearing a faint clunking in certain situations, mostly when moving left and right rapidly. Was able to reproduce it by shaking the car side to side by the door frame.

Jacked it up and instantly I saw the problem.

WP_20171126_17_25_03_Pro.jpg

This is what it is supposed to look like.

WP_20171126_17_24_56_Pro.jpg

My guess is it seized and then snapped in two. IIRC, this position (right front) always read a very different voltage than the rest of the sensors. I thought I've seen it move so maybe it was seizing and then finally seized completely before shearing into two pieces. Not sure I've heard of this but I'll poke around and see. I believe these are supposed to be life of car items.

Oh great. Rockauto carries Delphi which is what I'd want. They have all of them except the front right, and they are position-specific. The front left is $115.

Or I can buy an Airtex/Wells for $133.

I will try another source.

Interestingly, no Service Suspension warning yet. If the position value doesn't change when all the others do I'd think it will eventually set a warning and limit my speed to 80 mph. That will suck...I have to drive to Boston tomorrow morning. On the other hand, I've been hearing this noise for maybe a week now.

[kevm14]

Used one for $75:
https://www.ebay.com/itm/05-08-CADILLAC ... qb&vxp=mtr

Having trouble locating the right one as new. I could call Chris McCabe but I am traveling for the next 3 days.

Adam was saying something about locating parts for cars....can't remember what it was.

[kevm14]

This has got to be counterfeit:
https://www.ebay.com/itm/Delphi-ER10031 ... 1800725443

[kevm14]

Without calling Chris McCabe, I am down to used for $75:
https://www.ebay.com/itm/05-08-CADILLAC ... qb&vxp=mtr

Or the Airtex/Wells for $133:
http://www.rockauto.com/en/moreinfo.php ... 42&jsn=399

Interestingly, A1 Cardone and Standard Motor Products also does not have a right front, along with Delphi. Only Airtex/Wells does. Maybe it is an environmental troublespot being literally in the wheel well and more crappy stuff is on the right side (puddles along the side of road). In that case I probably don't want used since that one ships from Mass...

I guess I'll go with Airtex.

[kevm14]

For the record, my FE1 SRX (and an FE1 STS) has neither these sensors nor the ride leveling compressor. But FE1 doesn't drive nearly as well as FE3.

[kevm14]

My FSM seems to suggest that I can just throw a new sensor in there. No calibration or reset procedure required. I guess the ride height calibration is just for the air leveling compressor, not the MRC system itself. And it looks super easy. One nut, one plug. And the ride height link attaches to a ball stud on the upper control arm.

Maybe the same environmental conditions also caused this shock to leak, because it's leaking (Adam identified this when we first looked at it).

This would be about a $300 repair at the dealer.

[kevm14]

Drove to...well, Braintree.

No issues at all. Didn't even really notice anything different so I'm wondering if I will notice anything when I get the new one.

I am really interested in how the MR algorithms work. Like, right now it only has inputs from 3 sensors and I'd think the right front is just stuck on one value. But I guess what I'm wondering is how much individual wheels get damped differently than others. For example, if the inputs from the 3 sensors suggest....a bump. Assuming it isn't terribly confused with only 3 sensors, does it change the damping on all 4 shocks at the same time? Doubt it. But maybe each axle gets the same damping current? I mean the system is sophisticated enough to change the compression and rebound damping independently (it sort of fakes it - these are regular shocks so it would have to sense compression vs rebound and damp accordingly) on all 4 corners but....when does it do that? I guess that's all patented...

So if it drives dramatically different with the new sensor that may answer some of this...but what's also interesting is, the general approach with trouble code diagnostic routines tends to assume mechanicals are intact. In other words, GM may not have bothered making a code for "ride height sensor disconnected from upper control arm.". Rather, the code routines probably focus on voltage range and stuff like that, to ensure it is working electrically. Just kind of a feeling I have - goes with the fact that they also didn't try to diagnose my rear leveling pump when it wasn't making any air. They just assume that works fine, and stick to electrical type issues.

[bill25]

So this is GM pre code error/exception handling??? LOL

I think they had "try" statements in 2005. Definitely if then else...


This is a major reason that normal people don't want older luxury cars. It is not just that the prestige is worn out after 4 years and a new model is out. The amount of ridiculous unnecessary crap that is about to break is unfathomable. I personally like the exterior body style of the STS but I don't think I would ever want to own one...

[kevm14]

So this is GM pre code error/exception handling??? LOL

I think they had "try" statements in 2005. Definitely if then else...

I don't think they wanted to try to guess at mechanical problems.

Just like there isn't a code for "your timing chain jumped" but it can happen on some engines in certain circumstances. There can be timing correlation codes but again, you have to figure out the problem yourself. Without another layer of sensors for the original sensors, they wouldn't know if it was a chain or sensor issue. Sensors for sensors sounds like something the Germans would do so if you think the STS is too complex...

[kevm14]

This is a major reason that normal people don't want older luxury cars. It is not just that the prestige is worn out after 4 years and a new model is out. The amount of ridiculous unnecessary crap that is about to break is unfathomable. I personally like the exterior body style of the STS but I don't think I would ever want to own one...

It is. That said given the low cost of a Tech 2 now is the time to own something like this if you were ever inclined because I haven't needed any other kind of special tool so far.

I actually enjoy the idea of getting this car to 100% as there are a list of things I'd like to get to eventually, like engine mounts.