2000deville Posted July 27, 2005 Report Share Posted July 27, 2005 Hi there, I am brand new to the board, so I took my time and did a nice research before I decided to post -- unfortunately, I did not find a clear answer to my problem. So here I am, a happy caddy 2000 deville owner, for two years now without a major problem with my car. I bought it in 2003 with a nice mileage already on it (92K), and added another 30K till now (122K total) mainly without looking under the hood. But this summer a few problems occurred: the first one (and by most the most frustrating) is my AC -- it is acting wired: blow the cool air from the two passenger vent outlets, and really warm from the two on the driver's side; the cool air on the passenger side is also "not cool enough". First I thought (after the research made) it may something with my refrigerant; I bought R-134A kit and checked the pressure on the low pressure side -- all fine. There is also no warning message on my computer (if not counting a few other codes, but this would be my second question). So what is wrong? Can I help it myself (I am pretty handy, although am not a mechanic)? Please, advise. The second question is about the codes: I have three current: IPM BO429, PCM PO420 and PCM PO440. In the history there are: ABS C1287 and PCM PO 443. I also have two warning messages: "check your stability system" and "check your gas cup". I know it is a few questions in one posting, but I will appreciate any help and suggestions you may have (by the way: this forum is great!). Thanks for all responses!!! Link to comment Share on other sites More sharing options...
Scotty Posted July 27, 2005 Report Share Posted July 27, 2005 B0429 Air Mix Door #3 (rear) Range Error P0420 Catalyst System Efficiency Below Threshold (Bank 1) P0440 Evaporative Emission Control System (gas cap message) History P0443 Evaporative Emission Control System Purge Control Valve Circuit C1287 Steering Sensor Excessive Rate/Analog Mismatch Link to comment Share on other sites More sharing options...
2000deville Posted July 27, 2005 Author Report Share Posted July 27, 2005 B0429 Air Mix Door #3 (rear) Range ErrorP0420 Catalyst System Efficiency Below Threshold (Bank 1) P0440 Evaporative Emission Control System (gas cap message) History P0443 Evaporative Emission Control System Purge Control Valve Circuit C1287 Steering Sensor Excessive Rate/Analog Mismatch Thanks Scotty, This is what I have heard from my mechanic about some of it (and I am writing this, because he was not sure...): P0420 -- either a catalyst to be replaced OR just an oxygen sensor (nr1 front if I recall well)... Not a small difference in my opinion (!) P0440 -- just change the gas cap (which I did -- it helped for two days or so...) B0429 -- I am not sure... Now, this may be silly, but does the "history" mean that there was a problem but it is fine now? Thanks again, Blazej (2000deville) Link to comment Share on other sites More sharing options...
JimD Posted July 28, 2005 Report Share Posted July 28, 2005 All the sensors and related codes are handy diagnostic aids; but the system is not yet perfect science (even on the space shuttle). It is always a good idea to clear all trouble codes and see which ones are set again. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
Ranger Posted July 28, 2005 Report Share Posted July 28, 2005 "Current" means that the fault is currently detected. History means that the fault is not current but has been detected in the last 3 ignition cycles and will remain in history for the next 50 ignition cycles if not detected again, at which time it will be cleared. Link to comment Share on other sites More sharing options...
2000deville Posted July 28, 2005 Author Report Share Posted July 28, 2005 Thanks for the explanation of "current" and "history". It makes sense... I have cleared my codes for several times and they all come out again (looks like there are problems indeed...). I am just confused by not clear explanation of the problem by several mechanics I reported it to. Regarding P0420 they say so different things and the cost of repair various from $200 (oxygen sensor) to $2000 (catalyst converter). For P0440 I was told just to change the gas cap, but the problem came back again a few days later after I did so. And can B0429 be connected with my AC system? Does anybody have any idea about this wired AC malfunction that I am experiencing? Link to comment Share on other sites More sharing options...
KHE Posted July 28, 2005 Report Share Posted July 28, 2005 On multiple zone climate control systems, the most common cause of one side being warm and the other side cool is a low refrigerant charge. Despite what those "kits" with the cheesy low-side only gage tell you, there is no way to asses the proper refrigerant charge by a low pressure reading only. The only positive method is to recover the charge and compare the recovered weight with the full specification. I believe that those cars take 2.0 lbs of refrigerant. You can get close with a manifold gage set which has high and low pressure gages for reading both sides of the system. When adding refrigerant, use only straight R-134a - your car does not need leak sealer or o-ring conditioner. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Ranger Posted July 28, 2005 Report Share Posted July 28, 2005 B0429 is related to the HVAC system. It is telling you that the air mix door is out of range. It is most likely bleeding some heat when A/C is called for which would explain " passenger side is also not cool enough". As for the drivers side, it sounds like one of the air distribution door actuators broken, stuck or disconnected. First try running the temp all the way to 90 when in the A/C mode, then back down to 70 or so. Works for me when mine gets out of whack. Just a sticky actuator I suspect. If that doesn't work, remove the hush panel on the passenger side. Look up behind the glove box and you should see two actuators. One for the passenger side and one fo the drivers side. Have someone run the temp up and down and you should be able to see them move appropriately. You may find a connecting rod disconnected. You can access one from there but I believe the upper one has to be accessed by removing the glove box. Link to comment Share on other sites More sharing options...
2000deville Posted July 28, 2005 Author Report Share Posted July 28, 2005 I have done a small google research -- would it be a good solution: CPS Products MB34 R134a Economy Manifold Gauge Set? And if so, is there anything I should be aware of dealing with the high pressure? Thanks! Link to comment Share on other sites More sharing options...
jhall Posted July 28, 2005 Report Share Posted July 28, 2005 PO420 - This uses two O2 sensors at the converter - one in front and one in back. Measurements are made to determine proper function of the converter. The converter check is performed one time after starting once the converter reaches operating temperature. It's not the O2 sensors at the front or rear of the engine that cause this code. Different codes set when those sensors fail. One big caution is if you have a tank of gas with high sulfur content (known to happen once in a while) AND have a marginal converter, it will appear to the system that the converter is bad. Maybe try another station on the next fill-up if you frequently fill at one station only. Have a look at the converter for holes, discoloration and/or dents and make sure the O2 sensors, wiring and their connectors on either side are OK. Fill 'er up with a reputable station and clear the codes. If you don't see any damage to the converter or O2 sensors, you run a tank or more of good gas through the system and the code reappears, the converter needs to be replaced. Shop around on this - you should be able to get a better price on the labor. The converter prices range from $700 to $950 (California) good luck! Link to comment Share on other sites More sharing options...
KHE Posted July 28, 2005 Report Share Posted July 28, 2005 I have done a small google research -- would it be a good solution: CPS Products MB34 R134a Economy Manifold Gauge Set? And if so, is there anything I should be aware of dealing with the high pressure? Thanks! That should work. Make sure to hook up and disconnect the manufold with the engine off - allow the system to equalize to static pressure (high and low sides will be equal pressure) before disconnecting the hoses. Also, when adding refrigerant, NEVER open the high side valve or you run the risk of blowing the can... The air mixer door was for the rear outlets - I don't think that will affect the front outlets but it would be worth cycling the temp in the rear climate control to see if it clears up. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
2000deville Posted July 28, 2005 Author Report Share Posted July 28, 2005 I have done a small google research -- would it be a good solution: CPS Products MB34 R134a Economy Manifold Gauge Set? And if so, is there anything I should be aware of dealing with the high pressure? Thanks! That should work. Make sure to hook up and disconnect the manufold with the engine off - allow the system to equalize to static pressure (high and low sides will be equal pressure) before disconnecting the hoses. Also, when adding refrigerant, NEVER open the high side valve or you run the risk of blowing the can... The air mixer door was for the rear outlets - I don't think that will affect the front outlets but it would be worth cycling the temp in the rear climate control to see if it clears up. Thanks for a really good and clear explanation. No doubt I would have done a better and more professional job if I went with the manufold, but since I have already got the "simple low pressure kit", I decided to try with it first. AND IT WORKED OUT! With the ambient temperature of 75F my pressure was just 30psi -- I uploaded it up to 40psi (less than 1 12oz can of 134a) and I do enjoy my cool air again I do not know for how long would it last, but so far so good! "The air mixer door was for the rear outlets" -- that is also true -- the rear AC has not been working for some time now, but since it is just me and my wife who use the car, we had never really pay attention to it (although it is a shame to have such a great car with some systems disabled... Now, I have to take a look at my exhaust system (catalyst converter, oxygen sensors, gas cap, etc.) -- this really bothers me and costs me a fortune for the gas -- my gas usage looks like 10miles/gallon in the city and up to 17 on a highway!! Link to comment Share on other sites More sharing options...
JasonA Posted July 28, 2005 Report Share Posted July 28, 2005 Now, I have to take a look at my exhaust system (catalyst converter, oxygen sensors, gas cap, etc.) -- this really bothers me and costs me a fortune for the gas -- my gas usage looks like 10miles/gallon in the city and up to 17 on a highway!! There is something wrong with that. It should be at least 17 in the CITY, and closer to 25-30 on the highway. Perhaps the O2 sensor "problem" is really just a symtpom of another problem...one causing your poor gas mileage? Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
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