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OK, then if a P0200 you have either an open or a short to ground in your injector control circuit….I would remove the connector and do a “pin drag” test on the control circuit to check for poor pin fitment…if you remove both the injector and the PCM connector you can do a short to ground check with an ohm meter…the last one I helped a Forum member with was a short to ground..we elected to do an “overlay” then trying to find the wire that was near an inaccessible area.
OK, then if a P0200 you have either an open or a short to ground in your injector control circuit….I would remove the connector and do a “pin drag” test on the control circuit to check for poor pin fitment…if you remove both the injector and the PCM connector you can do a short to ground check with an ohm meter…the last one I helped a Forum member with was a short to ground..we elected to do an “overlay” then trying to find the wire that was near an inaccessible area.
St. Jude Donor '14-'15-'16-'17-'18-'19-'20-'21-'22-'23
Also check back by the firewall There is a black metal bracket where the wire harness wraps around it and will cut the harness. It should be on the left side behind the Intake manifold
OK, then if a P0200 you have either an open or a short to ground in your injector control circuit….I would remove the connector and do a “pin drag” test on the control circuit to check for poor pin fitment…if you remove both the injector and the PCM connector you can do a short to ground check with an ohm meter…the last one I helped a Forum member with was a short to ground..we elected to do an “overlay” then trying to find the wire that was near an inaccessible area.
Weird stuff has been going on, the code for p0200 has went away and hadn’t reappeared after probably 20 ignition cycles. but the car is still misfiring. my misfire table is disabled so i cannot figure out which cylinder is misfiring. i have a suspicion it is cylinder 6(tested temps with a. meat thermometer and it was colder than the rest by a 10 degrees, meat thermometer was all i had at the time don’t judge) The spark plugs only have 20k or so and the plug wires have maybe 5k, coils have never been replaced to my knowledge. is there anything else to consider before i test coils? i’m just confused as to why the code appeared and then went away (after snugging every connector) and the car is still misfiring, resistance tested all injectors and they were all within .2 ohm of eachother
Also check back by the firewall There is a black metal bracket where the wire harness wraps around it and will cut the harness. It should be on the left side behind the Intake manifold
Couldn’t tell you why the code went away possibly if it were a short to ground the chaffed wire may have moved a bit so it’s not touching ground any longer…don’t know what you meant by snugging the connectors but if you bent the terminals and tightened them up that may have been the cause…these “coil near plugs” are pretty bulletproof so I doubt it’s a coil pack…so what’s your coil pack testing procedure ??…there are a few more things that can cause a misfire like a clogged injector or something mechanical which you won’t be able to detect without doing a compression test and then there still are some things like a worn cam lobe or an exhaust valve that didn’t open and these will show as normal compression with an old school gauge….to determine which cylinder is misfiring if you have it disabled will be difficult but an infrared thermometer will work a little better and you can get a cheap one at Harbor Freight…I use a little more advanced method putting a pressure transducer in the tailpipe and a misfiring cylinder will cause a vacuum in that cylinder instead of exhaust gases being pushed out of the exhaust valve…a picture below of one I had done years ago…a colored “piston chart” helps determine which cylinder is on its exhaust stroke…this same pressure transducer can help determine if there is a worn cam lobe also but you could remove the valve covers and turn the engine over and see which rocker arm doesn’t move…so my advice is change plugs, wires, coil packs, injectors, and hope it’s not an injector or coil pack wiring issue, do a compression test and if good now you would have to look at the few things I mentioned…may be a broken valve spring…I found one of these broken springs last week on a 2013 with the big 427 engine (LS7)…that one had 0 compression and would hardly even run….didn’t even have to do a relative compression test with the scope as you could hear the uneven “cranking cadence” of the engine cranking it over…a short 4 second sound bite of it cranking is below…you may save yourself time and money by bringing your car to a diagnostic shop that uses these advanced testing techniques…all your other shops which are 99.999% will just change parts too.
Couldn’t tell you why the code went away possibly if it were a short to ground the chaffed wire may have moved a bit so it’s not touching ground any longer…don’t know what you meant by snugging the connectors but if you bent the terminals and tightened them up that may have been the cause…these “coil near plugs” are pretty bulletproof so I doubt it’s a coil pack…so what’s your coil pack testing procedure ??…there are a few more things that can cause a misfire like a clogged injector or something mechanical which you won’t be able to detect without doing a compression test and then there still are some things like a worn cam lobe or an exhaust valve that didn’t open and these will show as normal compression with an old school gauge….to determine which cylinder is misfiring if you have it disabled will be difficult but an infrared thermometer will work a little better and you can get a cheap one at Harbor Freight…I use a little more advanced method putting a pressure transducer in the tailpipe and a misfiring cylinder will cause a vacuum in that cylinder instead of exhaust gases being pushed out of the exhaust valve…a picture below of one I had done years ago…a colored “piston chart” helps determine which cylinder is on its exhaust stroke…this same pressure transducer can help determine if there is a worn cam lobe also but you could remove the valve covers and turn the engine over and see which rocker arm doesn’t move…so my advice is change plugs, wires, coil packs, injectors, and hope it’s not an injector or coil pack wiring issue, do a compression test and if good now you would have to look at the few things I mentioned…may be a broken valve spring…I found one of these broken springs last week on a 2013 with the big 427 engine (LS7)…that one had 0 compression and would hardly even run….didn’t even have to do a relative compression test with the scope as you could hear the uneven “cranking cadence” of the engine cranking it over…a short 4 second sound bite of it cranking is below…you may save yourself time and money by bringing your car to a diagnostic shop that uses these advanced testing techniques…all your other shops which are 99.999% will just change parts too.
Ran a temperature test again after the engine ran for about a minute, cylinder 6 is definitely the one misfiring as it was 100 degrees colder than the rest of the header tubes, i’ll try and mess with it again when i get a chance, just a question would a clogged/bad injector not cause p0200 code? also would it still ohm test normal?
The PCM is looking at the control circuit for an open or short…a clogged or faulty injector will not cause that DTC to set…below is from factory service information for a P0200…you can ohm out the injector if you want and the resistance is 11-14 ohms…btw, it’s always a good idea to let us know the model year as a MINIMUM.
The PCM is looking at the control circuit for an open or short…a clogged or faulty injector will not cause that DTC to set…below is from factory service information for a P0200…you can ohm out the injector if you want and the resistance is 11-14 ohms…btw, it’s always a good idea to let us know the model year as a MINIMUM.
Gotcha, i ohm tested all injectors and they were all right around 14, all within .3 of eachother. also the car is a 2001 my apologies, can one of the injectors still be clogged even if they resistance tested within spec?
An injector can be completely clogged and its resistance be fine…you can do an injector balance test with a fuel pressure gauge and one of these testers to see how clogged it is if that’s the case.
An injector can be completely clogged and its resistance be fine…you can do an injector balance test with a fuel pressure gauge and one of these testers to see how clogged it is if that’s the case.
Thank you i really appreciate the help, when i get the chance im going to test the coils/wires/plugs and if they all check out i will turn towards the injector. i appreciate you!
Well i would move the entire plug/wire/coil assembly to another cylinder and see if it changes where the misfire is. then narrow it from there and just check the plug/wire, and if both those check out then it’s the coil by process of elimination
If you have a 12 volt test light connect it to battery positive and then remove the plug wire from the coil pack as in the video and then back probe the light blue/white wire at C110 which is between coil packs 4 and 6…turn the key on and tap the back probe or a safety pin if you don’t have a back probe and you will see the coil pack fire !!…this is my 2008 and the trigger wire is easier to access since the connector is facing upward.
If you have a 12 volt test light connect it to battery positive and then remove the plug wire from the coil pack as in the video and then back probe the light blue/white wire at C110 which is between coil packs 4 and 6…turn the key on and tap the back probe or a safety pin if you don’t have a back probe and you will see the coil pack fire !!…this is my 2008 and the trigger wire is easier to access since the connector is facing upward.
Coil pack tested good, along with spark plug wire. i moved the cylinder 6 injector to cylinder 4 and will be testing again tomorrow(would’ve tested tonight but engine was already hot and wanted a fresh slate). if the misfire doesn’t move i will check the spark plug, thank you for all your help! any other tips if the misfire stays at cylinder 6 and the plug is fine?
If coil pack, plug and wire, and injector are all good then it comes down to mechanical…now a compression test will be needed to be done…if that is good there are still some things that can still cause a misfire as I mentioned…if compression test is bad then you will need to do a cylinder leak down test…piston at TDC on compression striker and introduce compressed air into the cylinder and see if you can hear where it is coming from….TB, tailpipe, or dipstick tube.
If coil pack, plug and wire, and injector are all good then it comes down to mechanical…now a compression test will be needed to be done…if that is good there are still some things that can still cause a misfire as I mentioned…if compression test is bad then you will need to do a cylinder leak down test…piston at TDC on compression striker and introduce compressed air into the cylinder and see if you can hear where it is coming from….TB, tailpipe, or dipstick tube.
Coil, wire, plug, and injector all came back fine. will be doing a compression test next, i’m kinda worried the injector harness might be an issue? my car doesn’t have the typical bracket that rubs through the wires so i’m not sure exactly where it would be messed up, and the p0200 code still hasn’t came back.
p0200 code please help
