2000 Deville Service Engine Soon Light

Justin J · #1 (**permalink**) 10-29-06, 01:06 PM

My 2000 Deville with 51,000 miles had the "Service engine soon" light come on. I felt that was just activated by the mileage saying it was time for a PM service. The light went out after another 100 miles. Now my AC stopped working. Checked the compressor and the clutch is not engaging.
My last Caddy a 95 Deville would have a message on the dash " AC low on freon turning off compressor to prevent damage" when it was low or out of freon. I would disconnect the battery to fool the computer long enough to check or add freon. Can I do the same with the 2000 without damaging something? I can't check or add freon unless the compressor is working.
Would you recomend purchasing a hand held Actron CP9125 PocketScan OBD II Code Reader for future problems and to prevent being "Had" at the service center

?

Thanks,
Justin

**Ranger** · #2 (**permalink**) 10-29-06, 05:11 PM

The SES light is not tripped by milage. If it is on, a fault has been detected and a DTC has been stored. You do not need a code reader to reade the codes. Go to the Tech tips sectionand see the "stickey" on how to pull them. Decifer them here.
http://myweb.accessus.net/~090/dtcobd2.html

To add freon, you have to enable the compressor. You can do that by pulling battery power or by entering the onboard diagnostics as mentioned above and clearing the DTC's.

Justin J · #3 (**permalink**) 10-30-06, 11:18 AM

Ran the codes.....

DIM P1540 ... A/C refrigerant over pressure compressor shut down.

What do you think is wrong with the AC? I disconected the battery to fool the computer and cleared all of the codes. The compressor still would not kick in. Do you have any suggestions as to what I can do?

Also code B0429 Temp #3 rear circuit range. Do I need to replace something? If so what and where is it located?

PS...
I ran the codes and cleared. The service engine soon light was still on when i turned the key off and on. After I started the car the code went away only to appear again when on turned the key off and on. What's up with that?

Thanks for your help it's really appreciated.

Justin

**Ranger** · #4 (**permalink**) 10-30-06, 06:00 PM

So you are not low on freon, thus the lack of the Low Refrigerant message. Obviously, it is the over pressurization switch that is protecting it. At this point a good set of guages with a high and low side pressure reading would be a big help and a FSM would be invaluable.

Caddyshack100 · #5 (**permalink**) 10-30-06, 10:31 PM

Other than what Ranger advised you, you mentioned a scanner. Don't waste your money on it. Your caddy can do all the things that scan tool can do and then some. That scanner will probably not read the airbags, abs, and all other computers that your caddy has, it will probably only read the powertrain. For other cars it will work well. A useful scan tool will run you nearly 1000 dollars, but for that you get the whole works, including bi-directionality.

Justin J · #6 (**permalink**) 10-31-06, 09:24 AM

Thanks guys for your help. Hate to but I guess I will carry it to the dealer.
Does it sound like a compressor? If so what would it cost to replace?

**Ranger** · #7 (**permalink**) 10-31-06, 11:50 AM

Hard to tell if it is a compressor or not, but if it has started to disintegrate internally, then the system has to be flushed, the orifice tube, accumulator and probably the condensor (unless they can flush it) will need to be replaced as well as the compressor. You might get off a little cheaper at an A/C shop, but in any case, be sure you are sitting when they give you the estimate.

Justin J · #8 (**permalink**) 10-31-06, 02:26 PM

I know it's going to be expensive. Would you say $1100 at a good local shop?
Could they flush it, refill and it could work?

**Ranger** · #9 (**permalink**) 10-31-06, 10:40 PM

You might get away a little less, depending on what needs to be replaced. Any good A/C shop should be able to flush what needs to be flushed and can be flushed, as well as vacuum down the system and refill it to get it working as good as new.

Justin J · #10 (**permalink**) 10-31-06, 11:59 PM

Thanks Ranger. I really appreciate all of your professional advice. I will carry the car to the shop, let them run a test and let you know what they find. I know if the system shuts down from high pressure it is normaly caused by trash in the system or a faulty High pressure switch. Let's hope it's not from the compressor coming apart from the inside on a 2000 deville with only 51,000 miles.

Thanks again,
Justin

**Ranger** · #11 (**permalink**) 11-01-06, 02:35 AM

One would certainly not expect a car with 51K to have a bad compressor, but stranger things have happened.

P.S.
None of my advice is professional. It is just a mix of expirience and what I have learned from the Guru. I have stood corrected more than once.

ewill3rd · #12 (**permalink**) 11-01-06, 06:46 AM

Usually excessive high side pressure is caused by a restriction in the orifice tube. It's likely you could have some compressor internal damage or possibly a failed dessicant bag.
Either condition would require replacement of the compressor however and it can be pricey depending on what route you choose.
I'd get a compressor from GM. I have seen too many problems with aftermarket reman units. It would be good if they change the orifice tube, flush the system and possibly install an inline filter in the liquid line. Most GM shops should be familiar with the procedure of adding an inline filter.
GM recommends them for any internal failure of the compressor because even if you flush it there could be some debris left behind that could clog up the orifice tube or damage the compressor.

I have seen failures on cars that were new, and cars that were really old. There is no telling what may have happened.

I'd agree with the previous posts in that you don't need a code reader.
Check Engine lights are not mileage sensitive, in fact they can't be according to Federal Law. There are rules dictating when the light can come on.
I know Chrysler used to use an "emissions maintenance reminder" light back in the mid 80's. I used to have to reset them all the time. They were indeed mileage sensitive and they were supposed to get you back into the dealer so they could look your car over and sell you something. Once folks found out about it, they stopped.
I think other carmakers did it, but I am not familiar with any specific examples.

That Model car has built in diagnostics that are more powerful than most aftermarket scan tools also. You don't need one.
If you upgrade to a Sigma car, you are out of luck, the new models removed this feature.
Be warned that some newer cars won't show you all the codes. Sometimes they are there but they won't display on the DIC when you do a code check. I can't tell you how often I get a 2000 or up with codes stored that won't show on the DIC but do when I check with a scan tool.
Not sure why that happens, but it does.

Hope this helps.

Justin J · #13 (**permalink**) 11-01-06, 08:01 PM

Something new! Started the car this morning and the AC worked. Pulled out of the drive stopped and opened the hood to listen to the compressor. It was very quiet. The AC lasted for about 5 miles and then it shut down. Started it 5 hours later and it worked with ice cold AC until I shut it off in my drive way 6 miles later.
What do you think? Loose wire? Bad high pressure switch? Trash in the line moving around? I am hoping now it might not be the compressor. What do you think?

Thanks,
Justin

**Ranger** · #14 (**permalink**) 11-01-06, 08:32 PM

Any DTC's?

ewill3rd · #15 (**permalink**) 11-01-06, 09:07 PM

Without hooking a set of gages to it, I couldn't even guess.
Any of the things you mentioned or none of them really.
Codes would be a good indicator.
Clear them and see if any come back.