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Discussion Starter #1 (Edited)
So, car was riding like a truck, so took it in and sure enough new front struts and rear air compressor system needed. As well as steering a steering wheel sensor? Anyway, now Service Engine Soon is illuminated, and I pulled the following codes: Anybody know what the letters before hand mean?
When I pulled the code list; it only had the A#### code listed, meaning a single letter with 4 digit code next to it. But I got IRC-U1000 and MSM-U1000 so are they two different types of U1000.

DDM U1715 - Loss of front door module to window motor?
DIM B1324 - A/C Refrigerant Overpressure?
PCM P0420 - Catalyst System Low Efficiency?
IRC U1000 - Class 2 Comm Malfunction?
MSM U1000 - Class 2 Comm Malfunction?
MSM ?2355 - Driver Vertical Sensor Malfunction?
MSM B1860 - Driver Lumbar Vertical Sensor Malfunction?
TTM U1016 - Loss of Communication with VCM/PCM


Any help and/or validation of these conditions will be much appreciated.
Just wondering what the impact is here... If these are accurate the only thing I think is of concern is B1324 - A/C Refer Overpressure.
OH... Forgot to add... the car does need brakes all around, but doubt that would illuminate the SES light

Thanks,
JC
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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The 3-letter codes are the module definitions, as in PCM = Powertrain Control Module, DIM = Dash Integration Module, and so forth.

Your SES is set by the P0420, O2 sensor fault. An emissions fault. It is probably NOT the convertor, but may be due to a vacuum leak. Start scrolling down the threads in Cadillac Technical Tips down below. Pages of info in there. Read the entire Cadillac Technical Archive up in the black bar ^^^.

The Uxxxx codes are hiccups, normally set by low battery voltage or voltage spikes on startup in cold weather.

More to the point, the letter C or H is more important: Current or History. If a fault is present for 2 or 3 start cycles, a C is set. If the fault does not occur for 3 start cycles, the code changes to H, and if the fault does not occur for 40 ignition cycles (a normal commuter week), the code self-clears.

Which car?? Update your signature with the car year and mileage. They're all different......I'm assuming the STS in this case.
 

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1997 Seville STS, 2000 Seville STS
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The P420 code is the one that turned the SES light on. Means your Cat is expended.
 

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STS
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Discussion Starter #5 (Edited)
The 3-letter codes are the module definitions, as in PCM = Powertrain Control Module, DIM = Dash Integration Module, and so forth.

Your SES is set by the P0420, O2 sensor fault. An emissions fault. It is probably NOT the convertor, but may be due to a vacuum leak. Start scrolling down the threads in Cadillac Technical Tips down below. Pages of info in there. Read the entire Cadillac Technical Archive up in the black bar ^^^.

The Uxxxx codes are hiccups, normally set by low battery voltage or voltage spikes on startup in cold weather.

More to the point, the letter C or H is more important: Current or History. If a fault is present for 2 or 3 start cycles, a C is set. If the fault does not occur for 3 start cycles, the code changes to H, and if the fault does not occur for 40 ignition cycles (a normal commuter week), the code self-clears.

Which car?? Update your signature with the car year and mileage. They're all different......I'm assuming the STS in this case.

YES... 2003 STS... BTW, the front engine mount was busted too so there was a lot of jerking around in there until this was fixed, so very well could be a Vac Hose somewhere... I'll check that this weekend... I know Cats can be expensive...

AND the P0420 is CURRENT the rest are History

Thanks
JC
 

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White Diamond '03 DHS (with DTS floor shift)
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There is only one CAT. It is upstream of the two mufflers.

DDM = Drivers Door Module
IRC = Integrated Radio Chassis
MSM = Memory Seat Module
TTM = Tilt and Telescopic Steering Wheel Module
"U" = Network Codes
 

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STS
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Discussion Starter #7
There is only one CAT. It is upstream of the two mufflers.

DDM = Drivers Door Module
IRC = Integrated Radio Chassis
MSM = Memory Seat Module
TTM = Tilt and Telescopic Steering Wheel Module
"U" = Network Codes

1 CAT Ok... Thought it might be like my Mark VIII with one behind each manifold... Never dreamed of replacing any of the exhaust on this so never looked down there... Thanks for the letter def's... Makes sense
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Whatever that picture is from it is NOT anything that will fit a transverse Northstar.

IF you feel the need to replace the cat, here's what you need..............www.easterncatalytic.com. Drop-in replacement for 2000-2004 Seville series. The newer Direct Fit series are all high-flow honeycomb units and leave the after-cat O2 sensor boss and hangers in the OEM pipe, so the new application looks like the pic but without the hanger and boss (pic 2).

BEFORE you start throwing money around get your car up on a chassis lift and take a good look at what you're replacing. Pictures and Internet advice are no substitute for your own eyes.
 

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99 STS, White Diamond
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So, car was riding like a truck, so took it in and sure enough new front struts and rear air compressor system needed. As well as steering a steering wheel sensor?

the only thing I think is of concern is B1324 - A/C Refer Overpressure.


OH... Forgot to add... the car does need brakes all around

Thanks,
JC
With active struts, shocks, level system, catalytic converter and brakes you're in for a hefty maintenance bill. Do you have a lot of miles?

The B1324 A/C Overpressure code can be caused by operation in extremely hot, humid weather (esp. stuck in traffic on blacktop) or a partly obstructed orifice and is likely the least of your maintenance concerns. If due to weather conditions, I guess it could be called "normal" but you could avoid by turning off the A/C when you really want it most... A partly obstructed orifice is usually an inexpensive repair.

Steering position sensors are a commonly replaced item. Do you occasionally get a chime and "Service Suspension System" message? If so, that's the sensor--if not, watch your codes as none you presented are related to the suspension system.

With the exception of the catalytic converter code, the DTCs you list can almost be considered "normal", especially if accumulated over months of operation.
 

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STS
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Discussion Starter #12
Whatever that picture is from it is NOT anything that will fit a transverse Northstar.

IF you feel the need to replace the cat, here's what you need..............www.easterncatalytic.com. Drop-in replacement for 2000-2004 Seville series. The newer Direct Fit series are all high-flow honeycomb units and leave the after-cat O2 sensor boss and hangers in the OEM pipe, so the new application looks like the pic but without the hanger and boss (pic 2).

BEFORE you start throwing money around get your car up on a chassis lift and take a good look at what you're replacing. Pictures and Internet advice are no substitute for your own eyes.

Thanks SUB... Sage advice; Will definitely take a look...
 

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STS
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Discussion Starter #13
With active struts, shocks, level system, catalytic converter and brakes you're in for a hefty maintenance bill. Do you have a lot of miles?

The B1324 A/C Overpressure code can be caused by operation in extremely hot, humid weather (esp. stuck in traffic on blacktop) or a partly obstructed orifice and is likely the least of your maintenance concerns. If due to weather conditions, I guess it could be called "normal" but you could avoid by turning off the A/C when you really want it most... A partly obstructed orifice is usually an inexpensive repair.

Steering position sensors are a commonly replaced item. Do you occasionally get a chime and "Service Suspension System" message? If so, that's the sensor--if not, watch your codes as none you presented are related to the suspension system.

With the exception of the catalytic converter code, the DTCs you list can almost be considered "normal", especially if accumulated over months of operation.

Swamp; Thanks... I have only 65,763 miles on this 2003 STS.
I did buy it used in '05 w/25K on it, but I think it sat for several months before I got it. That has its issues. Could tell by the amount of dirt on the bumper under the trunk deck. The car looks amazingly clean, both in and out. I do have DIAMOND Level Extended Warranty coverage until July 2010. By the way the struts were replaced already and the Steering Position Sensors... Good Call my friend!!!!

Thanks for the assist fellow Sevillans!!!
 

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1993 Eldo 4.9 66K miles
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OP,
You seem to have a lot of unrelated codes. A situation like this is sometimes traced to low battery voltage, and the codes themselves are bogus. You may want to check that before taking any further action.
 

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1990 Cadillac Eldorado 4.5 PFI
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I am not a cadillac guru, but I am a service manager with 10+ years experience in the automobile industry. A PO420 code is almost always a dead cat. Your cadillac, even without the Diamond extended service plan you have, has a 8/80,000 emissions warranty. It covers the PCM, catalytic converters, etc. Take it to the caddy dealer and have them scan the codes and let them know that you know what the code is and that it is covered under the emissions warranty. Assuming GM is still honoring warranties(just kidding:duck:) you will have your bad cat replaced under warranty. Good luck.
 

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White Diamond '03 DHS (with DTS floor shift)
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We know he is under 8 years old, but we don't know what his mileage is.
 

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2002 Cadillac STS w/ F55
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I would double check and make sure your struts were replaced with the MRC struts. I had my struts replaced by the dealership and they used the WRONG strut giving me service suspension system everytime I started the car up. Maybe they shredded some wires during the replacement process?
 

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STS
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Discussion Starter #20
I would double check and make sure your struts were replaced with the MRC struts. I had my struts replaced by the dealership and they used the WRONG strut giving me service suspension system everytime I started the car up. Maybe they shredded some wires during the replacement process?

Hey Thanks ALL... Struts were replaced with OEM Delco MRC struts...
Verified by Warranty Co...

Definitely CAT... Was idol in the parking lot of CVS waiting for my son to
come out from work and was smelling exhaust... was convinced then to take
it in... Going Thurs!!!

Thanks Again Cadillac Brethren :musical:

JC
 
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