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2002, Eldorado ESC
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19 Posts
Discussion Starter · #1 ·
I just bought an 2002 Cadillac Eldorado with 74,2xx miles on the car. This is my first Cadillac so I don't know much about the car and how the car computer works. Let me say I love the car here is the issue & I am hopping this should not be a cause for concern.

I drove the car home from the dealer and there were absolutely no issues on the drive home. I also drove the car for about 2 weeks with no issues. Then about 3 or so days ago the "service engine soon" light came on; there are now 74,4xx almost 74,500 miles on the car.

So I have a few questions? is this light a cause for concern? is this light a dumb maintenance light that came on because I am close to a 75k maintenance point? Also is there any way for me to see if there are any diagnostic codes I can get at without me having to take it into the shop?

Here is some other information that might help, since I have only had the car for a short time I don't have much and I don't know what the previous owner did to the car. The car has a clean history and all the recalls were done on the car so I don't think that is an issue. The shop did a work up on the car when it came into the dealership and this is a reputable company it is; (foothillstoyota .com) in Burlington WA and the oil life on the car is at 84% and I plan to change the oil at around 76,860 miles. I also know that it is not a head gadget issue there are no issues in the temp gauge and there is no discoloration in the oil. I have also done several WOT accelerations and the temp is fine.

I looked through the owners manual and the manual says it could be the fuel in the tank. I am not sure what the last owner did but the light did come on after I put non premium fuel and it was from the Costco gas station so I am wondering if the light came on because of the gas. Any Help on this matter would be great? I also would like to know as I said earlier, should I be worried, I don't want to throw a ton of money into a car if the repairs and diagnostics are going to be expensive.

Best Regards
Caleb McD
 

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1997 Cadillac STS (BOSE w/AUX In, Massage Seats, URPAS, "Z")
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6,405 Posts
Pull your codes, that tells you why the engine light is on. HERE!
No matter what the oil life says CHANGE THE OIL ASAP. It is just a matter of 5 seconds to reset it to 0 and save the dealership $50 while the car was on the lot.
Post your codes here and there is no "dumb maintenance light" is an issue that has to be addressed.

B.T.W Welcome!
 

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2002, Eldorado ESC
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19 Posts
Discussion Starter · #3 ·
I will grab the codes as fast as I can. also what is the best kind of oil to use in a car like this the dealer said use full synthetic however I have read everywhere that this is not a good idea and use normal mineral oil. What do you think or what do you use? Thanks for the welcome

Best Regards
Caleb McD
 

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'98 STS (RIP @ 206,xxx miles)
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4,854 Posts
....also what is the best kind of oil to use in a car like this....
Your year/model engine was driven away from the assembly plant with 5W-30 mineral oil in the crankcase. It's difficult (for me) to see any advantage to you to use anything other than 5W-30 mineral oil in your year/model of street-driven engine.

But, it's your car/engine plus your money which equals your choose. Oil is not a objective subject.
 

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08 cts 68k, 07 STS-V 15K, 97 Sts 160k
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302 Posts
I would have to agree change your oil asap. That way you know how many miles are on the oil for sure. It is easy to pull the codes from your car check out the link provided above but usually it is done by pushing the climate control off button and the temp increase button at the same time. Also there is what they call a drive cycle in which the diagnostics are completely run. Anyway I get the engine light some times and I know what it is so I turn on the AC for a while then the defrost for a while and some times then the light will turn off. What that does is lets the cars computer run through diagnostics of those systems. That tells me it is a history code and not a current code if it stays on then it is a current code and needs to be checked.
Bottom line is find out what the code is. Report back..
 

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2002 F55 STS, 2014 Explorer XLT, F-150s
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74,648 Posts
Get a real GM/Helm Service Manual from eBay or www.helminc. Or subscribe the car to www.alldatadiy.com. Forget the Haynes or Chilton's manuals. Too generic.

As posted by JimD, your engine will be perfectly happy using a name brand of 5W-30 oil, year-round, of whatever type - dino, blend, or synthetic - floats your boat. I am partial to WIX filters and Pennzoil Platinum synthetic and get around 5,000 miles/quart. (Your results WILL vary) WIX #51522 for the oil filter. The engine holds exactly 7.5 quarts with filter. This will bring the oil level to the middle of the dipstick hashmark: DO NOT try to keep the level any higher. That is overfilled and will lead to excess oil consumption. I habitually pre-fill the filter - the adapter on a Northstar makes this a no-mess job. When you do your own oil change, move the drain pan under the filter when you loosen it - you WILL get a half cup of oil draining out before you get the filter off, and it will be full to the top.

Go up to the black bar ^^^, read and study the entire Cadillac Technical Archive. Go down to Discussions; Item Specific; Cadillac Technical Tips. 9 pages of threads that will answer almost every question you may have.

The Oil Life Monitor (OLM) is accurate
. You reset it by holding down the RESET button for more than 5 seconds. If the oil presently in your engine is absolutely clear on the dipstick, run it for a while until the spirit moves you. If the oil in the engine is dark brown or cloudy, change it yesterday.

The SES light comes on because there is either an engine or emissions equipment fault occurring - do as suggested - pull the DTC's (Diagnostic Trouble Codes) from the car's built in system, write them all down, noting whether each is Current or History. Then return to the sticky "How to pull codes" and open the URL with "obd2" in the address. This will take you to a Master Index with links to all P,B,C, and U codes. Write down all the definitions and come back here.
 

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94 ETC,97 STS
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3,531 Posts
Computer control (on cars) is not magic, but you cannot see things happening so depending on how deep you are going to go you have to get the equipment to diagnose it.

I took a class (Comm College here has a great automotive program) on it to get a better handle on it. You can usually find fixes on the internet but it is good to get the "big picture".

I would recommend spending some time finding a web site that explains how it works... Fuel injection does just what a carb did, but does it electronically instead of mechanically, and does it better. You cannot see a varnished or clogged injector by looking at it, or a bad sensor like you could see an accelerator pump failure. Electronic ignition is the same, you can't look and see a bad module like we used to look at burned points. :cool2:
 

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2002, Eldorado ESC
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19 Posts
Discussion Starter · #8 ·
Alrighty folks I tried to pull the codes from the computer using the instructions above and maybe it is beginners bad luck or something but I can't get the DIC (Driver Information Center) to get me the codes the instructions on the external website state:

HOW TO "ENTER" DIAGNOSTIC MODE

To enter diagnostic mode, proceed as follows:

Turn ignition "ON." Engine can be either OFF or RUNNING.
Depress the "ON/OFF" button and the "UP ARROW" end of the info button on the driver information center simultaneously for a few seconds.

All the dashboard lights will illuminate, including the segments of the DIC display. You are then presented with text.

You can cycle through different questions using the UP and DOWN arrows on the info button.

first which on off button there are several is the radio a/c etc.
second what up arrow to the end of the info button and which end on the left or the right? I have a 2002 Eldorado ECS with a bose sound system and passenger side heating and cooling added in so to me everything look like button soup and I have tried several different combinations with no luck. so anyway sorry for the idiot question this looks so easy but I have a nack for bad luck i guess

Thanks for the help

Best Regards
Caleb McDaniels
 

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1998 Eldorado. Northstar "Y" code
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28 Posts
I have some pictures of the car if that would help anyone
I'm not sure if this'll work for you because your Eldo is 4 years newer than mine. But looking at your climate control panel, try pushing the "Off" and passenger temperature "up" arrow simultaneously.
On my Eldo this lights everything on the dash up. Then it will settle into the diagnostic mode. Any code that flashes will only be for a few brief seconds, so write them down quickly. Any codes shown will also tell you if they're current or history.
I hope that this helps you out and that someone else will chime in if this combination doesn't work for your Eldo's model year.
Once you get your codes, look up the corresponding description for it and post back here for the guys that can really help you out. Everyone doesn't have all the codes memorized, so it saves time if you post descriptions with the codes.
 

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2002, Eldorado ESC
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19 Posts
Discussion Starter · #12 ·
Alright Thank you Poncho's Eldo Got the codes! I have to say they sure go by fast and I also have to say that is one of the coolest things I have seen in a car ever! This is the only car that I have seen where a user can pull their own diag (Diagnostic Codes) without taking it to the shop or having special equipment!

Here are the codes

Current PCM code: P0420 Catalyst System Low Efficiency ( This is probably the cause of the SES light)

Now here is the past codes that were in the computer system in the order they came up

History PCM code: P0340 Camshaft Position (CMP) Sensor Circuit

History PCM Code: U1064 Loss of Communications with DIM

History PCM Code: U1152 Loss Of ACM Serial Data Communication

No IPC Codes were in the computer
No ACM Codes were in the computer

History SDM Code B1327 Vehicle system voltage below 9.0 volts

No TCS Codes were in the computer
No PZM codes were in the computer
No IRC codes were in the computer

History RFA code U1064 Loss of Communications with DIM

No CCP Codes were in the computer
No MSM Codes were in the computer
No MMM Codes were in the computer

Now I don't know what any of these things mean that is the downside. I went and looked up the definitions of the codes to make it easier on everyone. Could you guys explain the past issues and the possible causes so I can get some type of history on the car? But also and more important what is causing this current issue; is this an issue that should be dealt with ASAP or can I put it off for a while I just bought this car used and I have little to no money for major shop work and there is no warranty on the car. so this will all have to be out of pocket. :( Is this a sign that my N* motor is going to south for a permanent vacation or is this a minor computer issue? Also what should be the first thing I should have replaced if this is going to be a long list of repairs. & I hope that is not the case. Anyway, another note why did this light take two weeks to come on and did not come on right on the drive home? Also there is no driving performance issues that I can feel or hear. However that may be due to a very loud and squeaky fan belt that run squeaks when the car is very cold (i.e. is has not been run for at least 24 hours or longer) once everything is warm there is no sound at all from the fan belt. Anyway that squeak is a whole other issue. Any help in this matter would be great and you guys are the best. Thank you for all of the support this forum and the people in it were the ones who helped me decide on getting a Cadillac. Thanks everyone

Best Regards
Caleb McD
 

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2002, Eldorado ESC
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19 Posts
Discussion Starter · #13 ·
Sorry system doubled posted I have cleared out the second copy to keep the thread clean
 

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1998 Eldorado. Northstar "Y" code
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28 Posts
I'm a rank amateur to be sure. Only had my Eldo since Oct. 2010. I inherited and owned a 96 Deville for a short time back in '04 but never had any issues with it before I sold it. Since your only current code deals with the catalyst system I'm thinking that your drivetrain probably isn't "going south".
With any amount of luck submariner 409, Ranger, N*, Jim or one of the other more knowledgeable posters will help you out. I'm new here myself and am so glad to have found a forum where so many are glad to help out and have some patience with those of us who don't have a ton of experience with these things.
The fellas throw the acronyms out fast and furious here, I'm glad that they have the link to decipher them all! In the meantime maybe you could use the search function for PO420 to see what others have done about it.
 

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97 ETC
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84 Posts
Hi and welcome to the forum, this isnt very good news for you reguarding the P0420 code. You will more then likely need to replace your cat. You need to have someone that knows how to read and use a scan tool to see if all other components are working correctly but it looks like in the history you had a crank sensor code. If it was replaced thats good but it could have caused issues when bad that caused or causing the low effiency of the cat.

I dont remember if you got this car from a dealer and if so what kind of warranty did you get with it? If you do have a warranty dont clear the codes and take it back to them...

Good Luck
 

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97 ETC
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Also one other thing i will answer that you asked in the OP, I have run low octane in my ETC for ever with no issues so the answer is NO to the fuel causing the SES light to come on..now if it came on right after filling up and you left the gas cap loose and or you top off your car this can on some cars set a EVAP code..

Hope this helps
 

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2002 F55 STS, 2014 Explorer XLT, F-150s
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Your car is not going south and there are no "computer issues": the PCM (Powertrain Control Module) in these thing is darn near bulletproof.

All the History codes related to voltages and data loss are probably due to either a battery disconnect or dead battery. Not to worry - if you simply leave them alone they'll disappear in a few weeks of normal driving: codes that are not Current (the P0420) will self-clear after a number of start-run cycles during which the fault does not reset. ANY time you post fault codes, also post the definitions: None of us has memorized them all, but there are common ones............

Before you get paranoid over a bad cat, fill up with ($$$) 93 octane Shell, Texaco or Chevron on top of a 20 oz. jug of Chevron TECHRON (this gets repetitious) and go for a long highway drive - 100 miles - do some passing gear runs and work out the engine. Read the article up in Cadillac Technical Archive in the black bar ^^^ "Occasional full throttle operation...........". (Your engine has 3 O2 sensors: one in each exhaust manifold and one after the cat. The after cat sensor [B1S2] is saying "I don't like my reading as compared to the other two".) Run the snot out of it first, then start looking for needles in a haystack.

"Acronyms"........there's a link up top ^^ of this Seville page, and Google something like "gm automotive acronym list". Download one...........

BTW, the OP's car engine is spec'd for and will be perfectly happy on 87 octane - same as my STS.
 

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2002, Eldorado ESC
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Discussion Starter · #19 ·
Well that is not good; is the cat ( catalytic converter) if that is the issue how much would that cost? Also I did by the car at a dealer without a warranty and I but the car at a dealer all the way up in Burlington WA ( http://www.foothillstoyota.com/) so that is a two or more hour drive since I live in Fox Island/Gig Harbor WA. Also, forgive my down spirit but what can I make the dealer do?

Best Regards
Caleb McDaniels
 

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97 ETC
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84 Posts
Then i would clear it do as Sub suggested and see what happens. If it returns and its a P0420 Low Cat. Efficiency then have it looked at...

I belive I said in the earlier post that the P0340 was a crank sensor and I am correcting my self as its a Camshaft Position Sensor code that was in your history..
 
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