P 0300
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 17
Cadillac Seville / Cadillac Eldorado Forum Discussion, P 0300 in Past Cadillac Vehicle Discussion; 02 ESC. ONLY CODE IS P0300. Could a Crossover leaking badly have anything to do with the miss? New MAF,MAP,TPS, ...
  1. #1
    Ape4704 is offline Cadillac Owners Member
    Automobile(s): 2002 eldorado ESC
    Join Date
    Aug 2016
    Age
    44
    Posts
    15

    P 0300

    02 ESC.
    ONLY CODE IS P0300. Could a Crossover leaking badly have anything to do with the miss?
    New MAF,MAP,TPS, and plenum. Also fairly new IAC. Wanna find the cause of the miss before I embark on 6-8 hour surgery on the crossover.
    I also have an obd2 Bluetooth app. What kinda voltage should my o2’s read? Psi for MAP sensor? How many g/sec should the MAF read. Wondering if the MAF (last part changed) was bad out the box or possibly got the traditional post office treatment like a rugby match.

  2. Remove Advertisements
    Cadillac Forums
    Advertisements
     

  3. #2
    byrdman's Avatar
    byrdman is online now RIP Officer A. J. Casteneda
    Automobile(s): 2003 DeVille base, 149K miles
    Join Date
    May 2014
    Location
    Van Zandt County, Texas
    Age
    72
    Posts
    3,845

    Re: P0300

    P0300 is generic misfire. Your car's scanner won't tell you which cylinder. Get a parts store or shop read the codes. P0301 is cyl 1, etc. Once you know which hole is the problem, then fixing the problem becomes easier.

  4. #3
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    71
    Posts
    85,794

    Re: P0300

    Could be a small vacuum leak, or a dirty TB. When was the TB last cleaned?

  5. #4
    basscatt's Avatar
    basscatt is offline Master of the Dark Art of Diagnostics
    Automobile(s): 2003 DHS - two-2002 DHS's, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    67
    Posts
    18,419

    Re: P0300

    Quote Originally Posted by 1969byrdman View Post
    P0300 is generic misfire. Your car's scanner won't tell you which cylinder. Get a parts store or shop read the codes. P0301 is cyl 1, etc. Once you know which hole is the problem, then fixing the problem becomes easier.
    ---------------------------------------------

  6. #5
    basscatt's Avatar
    basscatt is offline Master of the Dark Art of Diagnostics
    Automobile(s): 2003 DHS - two-2002 DHS's, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    67
    Posts
    18,419

    Re: P0300

    ONLY CODE IS P0300. Could a Crossover leaking badly have anything to do with the miss?
    the crossover carries coolant from one side of the engine to the other -
    unless the coolant is leaking onto an electrical connection - I would say NO -

    MAF - MAP and TPS are all monitored and SHOULD set a code if malfunctioning -
    as are the O2 sensors -

    like byrdman said -
    P0300 is a generic misfire code -
    a hand-held scanner should be able to isolate WHICH cylinder is misfiring -
    P0301 = #1 - P0302 = #2 - P0303 = #3 - etc -

  7. #6
    Ape4704 is offline Cadillac Owners Member
    Automobile(s): 2002 eldorado ESC
    Join Date
    Aug 2016
    Age
    44
    Posts
    15
    Thread Starter
    Not using the dashboard code reader



    I’m using an obd2 app that can read individual sensors.
    For instance fuel system status says open loop due to system failure. My u derstandong is that is when the ecu doesn’t use the o2 sensors. That’s why I was asking what voltage I should expect for my o2 sensors. It tells me the volume of air (g/sec) my MAF is ingesting. The PSI that my MAP is reading. All why I was asking what acceptable ranges were for said systems.

    Also unles I’m mistaken a dtc code is set when a reading is out of desired parameter and for a specified period of time.
    Standard advice here is clean TB. Great advice and been done repeatedly. If I cleaned it as often as I’ve read the butterfly would have a hole in it.
    All joking aside ... I asked about the crossover because it carries recirculated exhaust gas thru the TB into the intake. Not a mechanic or engineer but with extra unmetered air/exhaust seemed like a potential problem.

  8. #7
    basscatt's Avatar
    basscatt is offline Master of the Dark Art of Diagnostics
    Automobile(s): 2003 DHS - two-2002 DHS's, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    67
    Posts
    18,419

    Re: P0300

    I’m using an obd2 app that can read individual sensors.
    some of you guys really like to make things as difficult and complicated as possible -

  9. #8
    Ape4704 is offline Cadillac Owners Member
    Automobile(s): 2002 eldorado ESC
    Join Date
    Aug 2016
    Age
    44
    Posts
    15
    Thread Starter
    been to the free scanner
    Is there no such thing as a p0300? Couldn’t it be possible I have a random/multiple misfire?
    In the FSM it’s listed as a DTC and I would bet not just because they tie our hands with the caddy dashboard dtc code method. ?


    This is supposed to be the place for answers. I would watch Jim Norton or other comedians if I want insults.
    I’m not a mechanic. Not auto at least but I install million dollar equipment what I don’t understand is the everything Cadillac (wish I did) I want my old car that I still love to be right not comments out the side of ur mouth. I could talk to my wife for that.

  10. #9
    Ape4704 is offline Cadillac Owners Member
    Automobile(s): 2002 eldorado ESC
    Join Date
    Aug 2016
    Age
    44
    Posts
    15
    Thread Starter
    Code read by box store scanner. P0300!!! Now tell me how I made it less difficult by driving somewhere to get the same info that I already stated. My scanner gives way more info like the “open loop fuel system fault” which I read means the ecu is not using the o2 sensors to control fuel trim and instead is using maf and map. Why I was asking what proper values for those sensors should be. No response but got snapped at instead.
    P0300 like I said to start with. No specific cylinder misfire it is a random/multiple cyl misfire

  11. #10
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it.
    Automobile(s): 2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
    Join Date
    Feb 2006
    Location
    MD Eastern Shore, Kent Island
    Age
    79
    Posts
    65,126

    Re: P 0300

    Finding the correct electrical values for sensors etc. can be tough. Try the diagnostic advice in the "All diagnostic codes" tab of the left menu in a www.alldatadiy.com subscription for your car - the online GM/Cadillac service manuals plus a lot more.

    IF the simple P 0300 code will not break down to a specific cylinder(s) then you are stuck with easter-egging (throwing parts at it) diagnosis. Usually a no-win situation.

    Have you removed and cleaned/checked the coil cassettes, plugs, and boots? Moisture and/or carbon tracked plug boots will cause random misses. How many miles on the plugs, boots, cassettes ? A bit of oil in one or more plug wells is of no concern - the well O-ring seals weep over time; oil is an insulator. Use ONLY the OEM AC Delco (DENSO) 41-987 double platinum plugs gapped to .050".

    The water crossover mounts the EGR but the exhaust gas is directed to individual intake port runners in the cylinder heads, not to the intake manifold.
    Attached Images

  12. #11
    byrdman's Avatar
    byrdman is online now RIP Officer A. J. Casteneda
    Automobile(s): 2003 DeVille base, 149K miles
    Join Date
    May 2014
    Location
    Van Zandt County, Texas
    Age
    72
    Posts
    3,845

    Re: P 0300

    Quote Originally Posted by Ape4704 View Post
    been to the free scanner
    Is there no such thing as a p0300? Couldn’t it be possible I have a random/multiple misfire?
    In the FSM it’s listed as a DTC and I would bet not just because they tie our hands with the caddy dashboard dtc code method. ?
    yes, you could have random misfires, but I'm surprised that you didn't find one or more cylinders stored in code memory. Simple stuff first. I agree with Ranger about possible vacuum leak.

  13. #12
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it.
    Automobile(s): 2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
    Join Date
    Feb 2006
    Location
    MD Eastern Shore, Kent Island
    Age
    79
    Posts
    65,126

    Re: P 0300

    Yup - here's another site definition of the generic OBD-II GM code series "P 0300". https://obdii.pro/en/code/P0300

    Absolutely nothing wrong with our built-in code systems - in many ways they're better than the handhelds because they use the code definitions that were current for the car in which the system was installed. Yes, the lack of a certain cylinder multiple misfire location is a drawback, but that's easily worked around at any parts store.

    http://www.cadillacfaq.com/faq/answers/dtccode.html

    MAF, MAP, IAC, O2 sensors - probably were/are not the cause of random missing. Focus on ignition first. Then fuel delivery and actual FPR pressures - pressure test set from any parts store. Schrader valve on the fuel rail. Fuel pressure spec is 41 - 47 psi at idle.
    Attached Images

  14. #13
    basscatt's Avatar
    basscatt is offline Master of the Dark Art of Diagnostics
    Automobile(s): 2003 DHS - two-2002 DHS's, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    67
    Posts
    18,419

    Re: P 0300

    Is there no such thing as a p0300? Couldn’t it be possible I have a random/multiple misfire?
    YES - but it is very - VERY - VERY - VERY - rare - but possible -

    In the FSM it’s listed as a DTC and I would bet not just because they tie our hands with the caddy dashboard dtc code method. ?
    one problem is that the on-board scanner will NOT display the specific cylinder misfiring -
    hence the suggestion to use a hand-held scanner -

    This is supposed to be the place for answers.
    you get what you paid for - this is a FREE and VOLUNTARY forum -

    YOU paid absolutely NOTHING -
    and looks like you have contributed absolutely NOTHING since joining -

    I receive absolutely NOTHING for my time or sharing my knowledge -
    EXCEPT the occasional THANK YOU from APPRECIATIVE members -

    the moderators receive absolutely NOTHING for their time -

    I would watch Jim Norton or other comedians if I want insults.
    like everything else on this site - insults are also FREE -

    I’m not a mechanic.
    REALLY? could have fooled me - ALMOST -

    Not auto at least but I install million dollar equipment
    should have stayed at a Holiday Inn Express -

    what I don’t understand is the everything Cadillac (wish I did)
    I have no idea what this even means -

    I want my old car that I still love to be right
    since you are NOT a mechanic -
    sounds like you should take the car to one - preferably a Cadillac Dealership mechanic -
    that should fix ya right up - but it won't be free -

    not comments out the side of ur mouth. I could talk to my wife for that.
    be sure to tell the service writer that when you drop the car off -

    GOOD LUCK - you're gonna need it -

    almost forgot - enjoy the forum -

  15. #14
    basscatt's Avatar
    basscatt is offline Master of the Dark Art of Diagnostics
    Automobile(s): 2003 DHS - two-2002 DHS's, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    67
    Posts
    18,419

    Re: P 0300

    Quote Originally Posted by Ape4704 View Post
    Code read by box store scanner. P0300!!! Now tell me how I made it less difficult by driving somewhere to get the same info that I already stated. My scanner gives way more info like the “open loop fuel system fault” which I read means the ecu is not using the o2 sensors to control fuel trim and instead is using maf and map. Why I was asking what proper values for those sensors should be. No response but got snapped at instead.
    P0300 like I said to start with. No specific cylinder misfire it is a random/multiple cyl misfire
    =====================================
    sounds like you already have ALL the answers -
    maybe you DID stay at a Holiday Inn Express -

  16. #15
    TenchiFreak5 is online now Cadillac Owners Member
    Automobile(s): Former 2003 Seville STS, 2016 ATS4 Coupe Premium 3.6
    Join Date
    Jul 2014
    Age
    29
    Posts
    16

    Re: P 0300

    For what it's worth, when I bought my Seville the previous owner was unloading it for a song because the dealer couldn't figure out a P0300 (that read as P0300 no matter what scanner it was hooked to) even after dumping all of the suggested parts into it (including plugs, front and rear cassettes, CPS and a plenum).



    I took it to my local mechanic soon after buying it. He hooked it into a Tech II and saw that it was shooting misfires on every cylinder nearly every crank rotation. Since it obviously wasn't actually doing that since it drove perfectly fine, he ultimately traced it to a damaged serpentine belt that was causing enough vibration in the motor (I'm assuming?) to fool the sensors. $65 later and the car was fine for the entire 5 years/~35,000 miles I owned it. Not suggesting that it's something so simple in your case, but these cars are both sensitive enough in self-diagnostic but primitive enough in computer power that it doesn't surprise me when they confuse one thing for something completely different.

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

What Cadillac(s) do you own? (Or type NONE)

Please select your insurance company (Optional)

Log-in


Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Read about Lincoln | Buick | Genesis | Kia Forte Forum