cad93 Posted July 19, 2005 Report Share Posted July 19, 2005 Newbie to this forum. I'm having a low refrigerent error on my 93 Seville with code A048. My low and high side pressures are ok and if I turn on the compressor by jumping the relay I do get cold air. When I clear the code it comes back within 30sec. When I check the ACP data I noticed AD33 is at -39 and doesn't change. I'm wondering which sensor is AD33?? When I disconnect the low side temperature sensor AD28 reads -39 When I disconnect the high side temperature sensor AD27 reads -39 When they are connected they read positive numbers and seem to work properly. Can someone help me with this AD33? I think this is why my compressor relay doesn't activate. BTW great forum and thanks for the help . Link to comment Share on other sites More sharing options...
Logan Posted July 19, 2005 Report Share Posted July 19, 2005 1993 service manual quote.....page 1C1 -4..... "AD33 is not used on this vehicle. Readings will be near -40 at all times." You are sort of on the right track. The first step is to look at the sensor values after a over night sit. All of the temp sensors should be rather close in value....maybe within 5%. I suspect you are just low on freon. These cars in a way calculate the freon charge based on temperture. Too cold and it will flag the service air message. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
cad93 Posted July 19, 2005 Author Report Share Posted July 19, 2005 Thanks Logan. It helps when you have a service manual. I've ordered one but it will take a few weeks before I can get it. Good to know AD33 isn't used. I just came back from a cruise in town and checked the sensor readings for low and high side and they were both at +43c. I will check again after an over night sit. When you say all the temp sensors do you mean just the low and high side sensors right? It would be nice to compare all the ACP data with someone. Link to comment Share on other sites More sharing options...
Scotty Posted July 19, 2005 Report Share Posted July 19, 2005 Where are you reading this data? On the DIC or a Tech 1 or Tech 2? Link to comment Share on other sites More sharing options...
cad93 Posted July 19, 2005 Author Report Share Posted July 19, 2005 I'm reading the data from the DIC. Link to comment Share on other sites More sharing options...
cad93 Posted July 20, 2005 Author Report Share Posted July 20, 2005 From all the forum searching I've done I'm suprised to see few postings on the actual data that can been seen on the DIC such as PCM data, IPC data, ACP data ect. All that data could be well served for trouble-shooting unless it's totally useless as I'm a newbie at this. Link to comment Share on other sites More sharing options...
Poobah Posted July 20, 2005 Report Share Posted July 20, 2005 There is a great deal of information that can be retrieved from the DIC (if you know how to do it and how to interpret it). One DIC feature that isn't discussed much here but I find interesting is the snapshot feature. When a code is set, a snapshot of the data relevant to that code is also recorded. Say, for example, you get a P039 code. You can go into diagnostic mode, answer "yes" to "PCM SNAPSHOT?" then scroll through to "P039 SNAPSHOT?". Answer "yes" and retrieve the data relating to that code at the instant it was set. If you know how to interpret the data, you can more clearly understand the nature of the code setting event. It is worth noting that the snapshots are not automatically cleared when the codes are cleared. If you are buying a car and find no codes, you can still see what codes were set recently by looking at the snapshots. All snapshots are cleared when the battery is disconnected, however. Happiness is owning a Cadillac with no codes. Link to comment Share on other sites More sharing options...
cad93 Posted July 20, 2005 Author Report Share Posted July 20, 2005 Interesting stuff. Hope I get my manual I ordered soon so I could look up my problem with ACP. Link to comment Share on other sites More sharing options...
Logan Posted July 20, 2005 Report Share Posted July 20, 2005 After a over night sit....this should be your first check with the AC system.. All the sensor values should be realy close value wise... AD21 Coolant temp AD25 In car temp AD26 Actual outside temp AD27 High side temp AD28 Low side temp Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
cad93 Posted July 20, 2005 Author Report Share Posted July 20, 2005 Thanks Logan ok I checked the sensor values this morning and they were all 23c except AD28 was 22c. So this tells me the sensors should be working properly. One thing I didn't mention before is a sensor which I believe is a pressure sensor between the accumulator and fire wall that isn't connected. I looked around for a connector and couldn't find one so I thought it wasn't used on the 4.9l. Am I right that it's not being used? Cleared the ACP ao48 error this morning started the car put the ac to auto and within 30sec the low refrigerent error appeared and the auto switches to econ. The compressor never turnes on. I know the relay is good as I switched it with another of the same type. You would think the compressor would at least turn on for a few seconds since the sensors readings seem to be ok at the start, then if a problem is detected by the sensor(s) shut down. As I said before I do get cool air when I jumper the relay. Thanks Link to comment Share on other sites More sharing options...
Ranger Posted July 20, 2005 Report Share Posted July 20, 2005 One thing I didn't mention before is a sensor which I believe is a pressure sensor between the accumulator and fire wall that isn't connected. I looked around for a connector and couldn't find one so I thought it wasn't used on the 4.9l. Am I right that it's not being used? If that sensor is not connected, the system thinks it is low on freon and that is why it is not working. Look closer. If the sensor is there, there has to be a connector somwhere. Link to comment Share on other sites More sharing options...
cad93 Posted July 20, 2005 Author Report Share Posted July 20, 2005 Well Ranger you hit it right on the nail! I thought the low side pressure sensor wasn't used at all for the 4.9l and only used for the 4.6l. After looking around for the connector I finally found it well hidden twisted around the main wire harness. The connector was jumpered and the jumper was all corroded causing the fault. The previous owner or garage must of jumpered it because of low r12 maybe and since r12 is illegal in Canada he didn't want to bother toping it up or converting to r134. So all in all it's working for now and if I get the low refrigerent fault I will have to convert to r134 to resolve the pressure problem. Thanks to all who helped. Link to comment Share on other sites More sharing options...
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