low refrigerant/ ac compressor off

[caddydeville05]

I have a 1997 deville and it says low refrigerant/ ac compressor off. What exactly does this mean and how do I go about fixing this problem?

Thanks in advance for any helpful advice.

[KHE]

Enough refrigerant has leaked out of the air conditioning system that the compressor has shut down in order to prevent damage to the compressor. There is a leak in the system somewhere. Inspect the refrigerant lines, compressor, & condenser for greasy/oily residue - that is where the leak is.

The compressors in these cars are belly leakers - because the aluminum ends are not painted, corrosion will eventually get under the case o-rings and cause a leak.

[Cadillac Jim]

You can also get that code when the compressor's reed valves go. That happened to me at about 120,000 miles, and the fragments took out the dryer.

[caddydeville05]

This is my first Cadillac to ever own so this is all new to me. I figured there was a leak bc I know you don't have to add freon that often. Also my gas gauge (range) was reading all crazy. I read where you could disconnect the positive side on battery for a few seconds so I did and the low refrigerant ac compressor off light went away. I drove around for a little while and all seemed well so I came home. About an hour later I was gonna go to walmart, got in car and it wouldn't crank. I unhooked the positive side on battery again but when I went to re connect it I hear a steady clicking noise coming from the fuse box located next to the engine. With that being said I can't even connect the positive side back without it clicking and am getting no power at all. I need help, I hope this is an easy fix.

[caddydeville05]

You can also get that code when the compressor's reed valves go. That happened to me at about 120,000 miles, and the fragments took out the dryer.

[caddydeville05]

Should I get a new battery? When the car didn't start and I disconnected the positive side on battery and re connected I went to try and start the car it didn't start then all of a sudden the trunk and the gas tank door popped open. I'm really confused! I don't have a clue how to check for codes or what they mean or how to clear them. Sorry if I'm being a pain in the *smurf* but like I said this is my first caddy to ever own so I'm tryin to learn how to do all of this.

[Cadillac Jim]

I believe that I replied to this question on the other thread that you started with the battery problem as the topic.

[caddydeville05]

Everytime I reconnect the positive side to the battery the Inadvert Power Relay fuse in my MaxiFuse box starts clicking.

[KHE]

You should disconnect the negative battery terminal FIRST or you run the risk of shorting your wrench on the frame which will give you a lesson in welding very quickly. After the negative side is disconnected, then disconnect the positive terminal. Reconnect the positive terminal first, then the negative terminal.

[Cadillac Jim]

I would put a trickle charger on the battery before I tried hooking it back up. Or, take it in and have it charged, and checked out.

[joeb]

Your car is 16 yrs old. We do not know how old the battery is. It may certainly need a new battery. And you should have the charging system inspected at least. You may get lucky and only need a bit of freon. But you also may have a leaky a/c component. Condenser, hose, even compressor. The typical a/c repair is evac system, check for leaks, recharge and than see how it works. Where are you? It's pretty cold in the US now. I hate it when car dies away from home. Now u need to pay for a jump, or a tow home. What's a new battery worth for peace of mind? If u were at Walmart, u could go in an buy a jump box for $45 or so. Cheaper than a tow truck.

[caddydeville05]

Ok guys I have a question. I went to get my ac system recharged and add freon. Got 1lb of freon added and was told my system was now full but still wouldn't blow cold. Apparently I didn't clear codes first in order for compressor to engage so my question is how did he add any freon if that's the case? So before I get the system evacuated and recharged I have to clear all codes, is that all I have to do to get compressor to engage and take the charge or should I also disconnect neg side of battery then reconnect? Thanks for any advice!

[barczy01]

You have to go into diagnostics and clear the code out. I head the low side pressure switch click always when charging and then i know its energized. The low side pressure sensors leak at the oring so just replace the oring and head to a hardware store to match it up. Also , the compressors leak bad too.

[KHE]

The system capacity is 2.0 lbs of refrigerant. BTW, Freon is a trade name that refers to refrigerant 12 (R-12), not R-134a.

[caddydeville05]

I actually don't have any current codes showing right now so that's another thing that is confusing me. I use to get the very low refrigerant ac compressor off notification when I turned the ac on but now that I went and got it topped off with freon even though it really didn't take the charge I no longer get that notification. I heard the compressors can leak to but obviously it would have to be engaged for me to tell but its still off. I'm completely lost as to how to get my ac working and its extremely hot right now it's killing me.

[caddydeville05]

U1255 is the only current code I have showing at the moment. Not positive but I think that has something to do with failed communication or something like that

[Cadillac Jim]

U1255 is a code that is thrown when a module is pinged but doesn't get back to the IPM in time. If it's HISTORY and doesn't come back quickly when you clear it, you can ignore it. A U1255 from the IPM every month or two is normal.

[caddydeville05]

That code has been current ever since I bought the car about 8 months ago. I've cleared it several times but it comes right back. I know my gas readings are out of whack. My range is way off and the gal it shows are wrong too. As I drive they both fluctuate like crazy. I've tried techron several times and have had no luck. Maybe my sending unit is bad but I'm not sure, what do yall think?

[Cadillac Jim]

Any code that is CURRENT or that returns immediately reflects a problem that should be addressed to keep the car fully functional. Most of them will result in a DIC message or a warning light. If you hav

The U1255 code can be thrown by several modules. You can tell which module threw the code by the sequence it is displayed in the DIC when you run the codes. When you run the codes, the IPM will interrogate the modules in order, beginning with the PCM and IPC, then ACM, SDM (air bags), TCS, RSS (if you have RSS), PZM (body), then IRC (radio), RFA (key fob), then CCP (climate control panel), then modules for whatever options you have on your car. If a module has no codes, you get a message like "NO PZM CODES." If you do get a code, it has a format like "IPC U1255 CURRENT." Tell us exactly what is displayed with this code so we can identify the module that is throwing it. Then we can use the car's schematics to tell you where to look.

[caddydeville05]

Ok thanks for the reply. The current code I have is IPC U1255.

[caddydeville05]

Another thing I might add is my trunk latch isn't working properly and also not sure if it has one of those motors that when it catches the motir closes it all the way? I took the two bolts off and turned the latch clockwise twice to where it lowered the latch where it would be if it was closed all the way. With that being said, now everytime I turn the car on I get the DIC message that the trunk is open. Do you think that could be throwing the code? Just a thought.

[Cadillac Jim]

Your car has a trunk pull-down. I sold my 1997 Cadillac a couple of months ago and never had the problem myself. If you are getting a message on the DIC, there will be a code that reflects why the message was thrown. It isn't the IPC U1255, though.

If you are getting a hard U1255 from the IPC, one of the other modules is either off-line (the PPL wire in it's connectors is broken or the connection is loose) or a module is dead. A fuse can cause this.

You should have other codes. Are you reading these from the DIC using the car's computer?

[caddydeville05]

Yea I'm getting that code from the cars computer. I had the cat converter code and the sensor in front of the cat code current last week but I just got those two things replaced over the weekend so those codes are both history now. As of today the IPC U1255 is the only current code showing when I run the diagnostics from the caddy computer.

[Cadillac Jim]

First, if you are getting no A/C codes and it still isn't blowing cold air, then the ACM may be offline.

When you turn on the key (or begin the process of reading the OBD codes) all the dash lights come on for a few seconds. Check to see if any of them are NOT coming on. First, all the lights should come on, then the MIL and oil pressure lights should be on when the key is on, but the engine isn't started.

When you run the codes, look for the sequence of modules PCM,

Look in particular for the ABS and TC lights. If you don't see them, a fuse may be out for the ABS/TC module (the EBTCM) or the RSS module. If those lights don't come on when all the rest come on, the EBTCM is offline, probably because of a fuse. You can check by pressing the TC button in the glove compartment and seeing if you get the "TRACTION CONTROL DISABLED" message on the DIC.

Run the codes again and look for this sequence of modules: PCM, IPC, ACM, SDM, TCS, RSS, PZM, IRC, RFA, CCP, MSM, MMM, PHN. If there is an overly long pause before any one of them that stands out as longer than the pause before the others, make a note of which one.

The MSM is the memory seat module and the MMM is the memory mirror module. If you don't have one of those, then the module won't be in the list.

If you don't have OnStar or a car phone, the PHN module won't be there. If you have *ever* had a car phone, either the kind with a cord or a cordless car phone, you will have a phone module. If the car had a phone and someone took it out and pulled the fuse or connector, then unless some knowledgeable person "told" your IPC module that the phone was disconnected you will get a U1255 and a long pause, then "NO PHN CODES." The best way to handle a removed phone is to leave the module in and connected but tell the IPC that the phone is not installed with an override. We can tell you how to change the overrides but it's not for the faint of heart and there is some risk involved; some people let the dealer do that.

The PCM module is OK because the car runs, and the IPC/DIM module is OK because you can read the codes, and the CCP must be working because you use the buttons that operate it to run the codes. If the radio and the key fob work, the IRC and RFA modules are online.

Thus the main candidates for being offline that aren't easily checked are the ACM, the SDM, the TCS or RSS, the PZM, the IRC, or the MSM/MMM/PHN. Watch for long pauses before the "NO XXX CODES" message when you run the codes.

FUSES

You have two main fuse blocks, one in front of the left strut tower under a plastic door and the other in the trunk on the left side behind the trunk liner. The fuses to check, and the modules that they power, are:

50 Amp BRAKES Maxifuse, RH MAXIFUSE block under the hood. (EBTCM)

50 Amp BODY 1 Maxifuse, LH MAXIFUSE block under the hood. (RSS)

50 Amp BODY 3 Maxifuse, LH MAXIFUSE block under the hood. (IRC, PZM, IPM)

50 Amp IGN 1 Maxifuse, LH MAXIFUSE block under the hood. (SDM)

10 Amp MIRROR fuse, engine compartment fuse block (MMM)

10 Amp ABS fuse, engine compartment fuse block (EBTCM) <== check this one carefully!

10 Amp ECS fuse, engine compartment fuse block (PCM)

10 Amp CRUISE fuse, engine compartment fuse block (A/C low pressure switch)

20 Amp DIS fuse, engine compartment fuse block (IC, or ignition module)

10 Amp PCM (IGN) fuse, engine compartment fuse block (PCM)

10 Amp PCM (BAT) fuse, engine compartment fuse block (PCM)

10 Amp A/C COMP fuse, engine compartment fuse block (not a module but powers the A/C clutch)

10 Amp IGN 0-BODY fuse, trunk compartment fuse block (PZM, ACM, IPC, CCP)

20 Amp PULL DOWN fuse, trunk compartment fuse block (not a module but powers the trunk lid pull-down)

10 Amp BATT fuse, trunk compartment fuse block (MSM)

20 Amp SIR fuse, trunk compartment fuse block (SDM)

10 Amp RSS fuse, trunk compartment fuse block (RSS)

10 Amp RLY IGN 1 fuse, trunk compartment fuse block (PZM, ABS/TCC switch in glove compartment, IPC)

10 Amp COMFORT fuse, trunk compartment fuse block (PZM, ACM, RFA)

10 Amp RSS Fuse, trunk compartment fuse block (RSS)

10 Amp PZM fuse, trunk compartment fuse block (PZM)

30 Amp AMP fuse, trunk compartment fuse block (IRC when Bose radio is present)

30 Amp AMP fuse, trunk compartment fuse block (radio audio amplifier without Bose radio)

[KHE]

Another thing I might add is my trunk latch isn't working properly and also not sure if it has one of those motors that when it catches the motir closes it all the way? I took the two bolts off and turned the latch clockwise twice to where it lowered the latch where it would be if it was closed all the way. With that being said, now everytime I turn the car on I get the DIC message that the trunk is open. Do you think that could be throwing the code? Just a thought.

Many times a malfunctioning trunk pulldown can be traced to a broken upper latch switch which is caused by people slamming the trunk. Unplug the switch and use an ohm meter to test the switch.