Clusco - This code means that the Electronic Level Control is not working. There are two main parts to the ELC system, an air pump and a solenoid exhaust valve. The code is telling you that the exhaust valve is busticated. On my car, it was rusted out inside and not working. The ELC fuse would pop instantly after replacing it. Yours is probably popped right now.clusco said:What exactly does this code above mean on my 1999 STS and how do I fix it?
The mechanic is right - it is an electrical issue, as indicated by the code description. Congratulations to him for having the ability to read. Unfortunately he didn't give you anything useful beyond that apparently. The electrical issue in my case was that the solenoid was badly rusted internally and that's where the short was, hence the electrical issue. It's possible that there could be a short elsewhere, so while you're down there, carefully inspect the wiring for frayed spots and bare copper that could be shorting out. My guess is you'll find the wiring to be just fine and the solenoid will be badly corroded and rusting internally.clusco said:I talked to a mechanic at the local Cadillac dealership here in town and he told me that it is purely an electrical issue if that particular code comes up.
Mcowden, are you saying that the solenoid could be bad but to replace it you must replace the entire pump?
You don't have to change it out at all if you don't want to. The purpose of the thing is to determine the level of the rear of the car by the position of the suspension and bring the car to a standard height by raising or lowering the pressure in the rear air shocks. If you don't fix it, the rear of the car will not self-level. I don't know if it affects anything else or not. If you just unplug the compressor the code might go away. I don't know about that, though because I've never tried it.clusco said:What exactly is the purpose of this electronic level control and how long can I go before changing it out?
The rims have nothing to do with the code directly, but it's possible one of the air lines was dislodged or damaged when you were working in there. If that happened, it could have let water into the system and contributed to the solenoid problem, but that would take a while to happen. If the code started soon after you replaced rims, I would say it's an unrelated event. The offset has nothing to do with this. It's an electrical problem, plain and simple, as the dealership mechanic already informed you so helpfully. The way to resolve it is to follow the steps I outlined above.clusco said:That raises an interesting point for my situation......
I just bought this 1999 STS last week and the code hadn't come up before. Previously I owned a 1995 STS and when I bought this newer STS I switched the "factory" rims from the '95 to the '99.
After I switched the rims, periodically the message, "SERVICE STABILITY SYSTEM", will come up from time to time. Could my switching the rims have affected this C1738 code to come up, perhaps a different offset?
And if so, is there an idle learn procedure to perform to make the '99 "get familiar with the dimensions of the its new rims' offset?
One last thing............ The SERVICE STABILITY SYSTEM message came up a lot when I first changed the rims out and now it hasn't come up in about 7 or 8 drives on the road.
Wow! That's excellent information, Privateer, thank you very much for posting all of that. The ELC compressors and solenoids do go bad, and this question comes up from time to time. Your post will help someone down the line. Good work on the solenoid replacement! :thumbsup:Privateer said:I just went through this last week with mine. 99STS, same code etc. I noticed for a few days that my compressor was running for a long time after start up and the car was not leveling. I went under the car and found one of my air bags on the rear shocks were leaking so I unplugged the 30 amp fuse under the back seat to shut the compressor off. It didn’t seem too bad until I priced them at $600.00.....EACH. But I had to have them, couldn't live with an STS with passive struts so I replaced them.
The sting had not even worn off when I got the code C1738. The struts pumped up great but would not come down at all. Every engine start cycle, when it test ran for a few seconds, would pump it a little higher without re-leveling. Not having the time to do any thing right away, I had to pull one of the hoses on one of the struts to release the air to level the car again and pull the fuse again.
The fun started when I had to drop the exhaust system to remove the compressor assembly. Luckily they have a flexible section in the exhaust pipe which let me lower it enough without disconnecting it.
The compressor ran fine but when I applied 12VDC to the solenoid no click...frozen. I pulled the head plate off, like 6 or 7 5/16" screws, and the solenoid was corroded and full of water from running continuously with the leaking air bag. The dryer was also full of water and probably the air lines.
The solenoid is not sold as a single part but the head assembly which includes the dryer is ( part # 12494810) for around $150.00. That’s if you can find one. My Florida parts guy couldn’t find one…anywhere in the country… and the $500.00 complete pump assembly which included the dryer was three days away ( part # 12494809).
I had to take an old solenoid out of an old Delco pump, cut the wires to the dead Cadillac one and use stake on connectors to connect the new(old) one.
The original Cadillac pump was sealed much better and directly wired to the solenoid. The older version, at least 12 years old, had the spade type connections which I had to bend over to clear the heat shield. I had to use the old head plate because the newerCadillac head plate had a different opening for the solenoid connection. Even after all these years the pumps were basically the same. I had to silicone the solenoid electrical penetration through the head plate to seal it better and it worked great… for now. I KNOW this exposed connection is not going to last very long but hopefully long enough to locate the head assembly.
One important thing about removing a good solenoid from an old head. Pry it straight away from its air connection. It has a little nipple on it with an O ring which fits into a hole in the side of the head. If you try to pry it “up” the nipple will break and… Oh Well…what was that junk yards phone number again?
I blew the dryer out with dry nitrogen until no more moisture came out, blew out the air lines, replaced the rubber air lines and tee fitting at the compressor which turned to dust when I touched them and re-installed the whole thing. Code gone. Car level.
Sorry for the long winded story. I hope it helps .
If the solenoid is shorted, the ELC fuse is probably blown. In that case, the compressor will not run. The ELC depends on correct functioning of the compressor and the solenoid. If one or the other fails, the entire system is useless. Check the ELC fuse and let us know. On my '96 it's in the fuse panel behind the rear seats, accessed by removing the carpet behind the seats in the trunk. I'm not sure where the fuse is on your car, though.clusco said:Okay, for the code that I have acquired on me '99 STS, I understand that my exhaust solenoid has gone bad BUT to replace this part, you must change the entire compressor?
So if this is the case, I'd like to know how serious of a problem this is. If the solenoid is bad, does this mean that the compressor is not working at all or simply that the solenoid isn't sending a signal to my computer? The "SERVICE STABILITY SYSTEM" message only comes on every so often. For instance if I start up the car and drive down the road the message may appear if I swerve or slam on the brakes but if THEN at other times the message won't appear at all during a drive. So my question is: Is the car's ELC functioning properly before the message comes up on the display panel?
Lastly, if I do have to change the compressor set-up, is it relatively easy DIY job?
I know I typed a great deal here but any help is much appreciated and desperately needed. Thanks!
Ranger said:Fuse block on the '99 is under the rear seat cushion.