1999 Cadillac SLS help

1999 CADILLAC SLS
184,000 MILES • V8 • FWD • AUTOMATIC
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ASTRAIGHTIFF
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  • 1 POST
I have a 1999 Cadillac SLS. I am getting a message on the display service AC system. I am able to run a diagnostic on the system. In order for me to be able to run this test, I had to look up a 2000 model. The 1999 model would not work. I am able to reset the code, and the compressor will come on for a brief second. I would like to check the system but am unable to find the low presser test point. Can you help me out on this? Here is the list of codes. I am hoping you could tell me what they mean? My email address is aastraightiff@live.com

Thank you,
Albert

ABS= no code
AMP= no code
DDM= no code
DIM= B1324 History
IPC= no code
IRC= no code
PCM= P0533 current
RFA= no code
RIM= no code
SDM=no code
VTD= B2947 History
MSM= B1860 History
TTM= no code
RSS= no code
Jul 9, 2009 at 9:09 AM
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FACTORYJACK
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It looks like the p0533 and b1324 are the ones to be concerned with. They both mean the same thing. You have a pressure switch fault indicating high pressure(in excess of 430 psi). I believe the sensor is in the smaller line down near the compressor. Check and see if it is plugged in. The DIM is seeing 5.00 volts on this sensor, which indicates high pressure. You could have a sensor fault, disconnected or poor connection, open wire, or faulty DIM. The pressure ports are at the rh end before and after the variable orifice, by the underhood fuse block. The three wires at the sensor are: Pin A(black) to pin 50 at pcm, Pin B(gray) to pin 67 at pcm, and Pin C(red/black) to pin 56 at pcm. Pin b is the 5-volt line, pin a should have continuity to ground. If all else fails. check wire continuity of each wire from the sensor to the pcm. All the wires are in the blue pcm connector.
Jul 9, 2009 at 10:44 PM