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P1189


Mary

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Sorry! Here ya go..PCM P0300H, PCM P1189C, IPC B1552H, IPC U1255C, ACM B1341H, ACM B1348H, PZM 1552H, PZM 1558H. That's after I disconnected the battery and drove it around. I really appreciate this!

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The P1189 Current is the one still causing the SES light.

Did you still feel a misfire at first and then it went away after you drove it a little?

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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I'm sorry, the P1189 will NOT turn on the SES light and the U1255 will NOT turn on the SES light/message either.

Back to the FSM. :unsure:

Which light/message are you seeing?

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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OK the P0300 is causing the SES. 

Start the engine and let it idle for a couple of minutes. If the SES msg/light comes on then be sure to leave the engine running and enter diagnostics, see if the P0300 is current.

Sorry, I had a brain fade. The P0300 was showing history, so I was thinking the code wasn't clearing. :blush:

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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A cylinder misfire is caused by the cylinder not firing evenly, or at the right time.  Proper operation requires fire (spark), fuel, and air, all to arrive at the cylinder at the right time.  To diagnose a misfire, we begin to validate each of these components.

That's why Mike mentioned coil packs, which provide amperage to the spark plug wires to fire the spark plugs.  Coil packs are a maintenance or wear item -- they end up needing replacement at some point.  As are spark plug wires, spark plugs, and to a lesser extent injectors. What we don't want to do is just start replacing parts though, we want to look for clues to help us determine what part(s) are not working.

Our prime suspects are Fire: coil, plug wires, or spark plug; fuel: injector, clogged fuel filter; air: clogged air filter, coked up intake; timing, which seems unlikely so far.

Have any of these parts ever been replaced to your knowledge?  

 

Bruce

2023 Cadillac CT4-V Blackwing

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I'm just running the codes on the dash. Hmm. I did feel it misfiring still. It did stop and the SES light didn't come on for quite a while but then it started blinking then went solid. I guess I will have to take it in. The guy that helped me with my battery seemed to think it could be my fuel filter causing the misfire. Is that possible?

 

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it is less likely; if the fuel filter is clogged to the point that fuel is short to the cylinders it would tend to impact all of the cylinders -- so the engine would die -- not one cylinder like a misfire condition.  It is possible though, and the external filter is relatively easy to change but may not be something you care to do for the first time.  This video addresses fuel filter change on a deville:

 

Bruce

2023 Cadillac CT4-V Blackwing

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The P0300 is something for someone more experienced and with a wider choice of diagnostic tools than the at home tool kit. 

The reason the light flashes and then goes steady is because the computer is telling you there is the possibility of damage to the catalytic converter, or other emission related components.

I wouldn't worry too much about the fuel filter at this time.

Take the vehicle to a Cadillac dealer or a reputable auto repair shop and TELL them you only want the P0300 diagnosed and a list of the cylinders that are misfiring. This should only cost you a half hour of diagnostic time. Be sure to tell them NOT to replace any parts without calling you first.

When they call you and give you their diagnosis of the problem, post it here and we can make sure they are not taking advantage of you.  

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Okay, great. Thank you so much! I really appreciate all of your help. I'll take it in this week then post it and see what you have to say! Thanks again!

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The plan is diagnosis first then decide on fix.  If they say spark plug wires, or spark plugs, it is normal to change all 8 of either at the same time if one wire or plug needs replacement.  Injectors I think are often changed one at a time due to greater expense, less frequent failure.  Generally, dealer pricing is 2x on parts and $100/hour on labor so figure that in your do it yourself trades.  

There is a big temptation to just let them fix and be done with it, so you may want to set a low price going in that if it is more than say $250 to fix then just "tell me the diagnosis and I will have my mechanic address" or similar.

They will also likely tell you the transmission fluid needs a change, and the throttle body needs cleaning, radiator flush, and other maintenance items.  Generally simply decline anything except the miss issue related items.  My STS-V they told me throttle body needed cleaning every visit; when I pointed out for that engine the throttle body check would require taking the whole intake apart and cleaning would be a whole pain since the throttle body faces the firewall they confirmed yes, they recommend as a blanket policy without checking.

rockauto.com has good prices on discount new original equipment parts once we know what part(s) are needed.

Bruce

2023 Cadillac CT4-V Blackwing

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It may just need a tune up, plugs, wires, there could be corrosion at the coils where the ignition wires connect, water can leak an get the area wet

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Try opening up the hood at night, and look under the hood for any flashes.  I agree that this might all be solved with new plugs and wires.  Did the problem go away when it was dry out, then it rained, and the problem came back?

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