Ignition coil misfire
#1
10-07-2023, 03:30 PM
Ignition coil misfire
I have 2007 Camry XLE v6 3.5L, I keep getting ignition coil misfires even after changing all ignition coil and spark plugs.
Initially I had 0355 code and then later 0354 and 0351 so changed all the ignition coil and spark plugs.
It has been quite intermittent, ignition coil misfires and then gets corrected automatically but lately its pretty consistent misfires. It happens during idling and driving.
What could be going on with my car? Any suggestions? I am not sure what should I do next, I have been reading fuel injection could be problem or it could be ECM/ECU issue. I am not entirely convinced on ECM issue, few questions: 1) Can bad ECM damage ignition coil -assuming ignition coils were new? 2) Can bad ignition coil damage ECM? 3) How to check ignition coil itself is bad? Can resistance between any of the 4 terminal be checked to find this out ? 4) How to confirm ECM side plug is fine, Can resistance be measured between pins to confirm? 5) Could it be fuel injector problem? How to narrow down it further? I had been to multiple mechanics but no success, everyone does something or other but problem isnt solved. Any help is appreciated ? Thanks Arvin
Initially I had 0355 code and then later 0354 and 0351 so changed all the ignition coil and spark plugs.
It has been quite intermittent, ignition coil misfires and then gets corrected automatically but lately its pretty consistent misfires. It happens during idling and driving.
What could be going on with my car? Any suggestions? I am not sure what should I do next, I have been reading fuel injection could be problem or it could be ECM/ECU issue. I am not entirely convinced on ECM issue, few questions: 1) Can bad ECM damage ignition coil -assuming ignition coils were new? 2) Can bad ignition coil damage ECM? 3) How to check ignition coil itself is bad? Can resistance between any of the 4 terminal be checked to find this out ? 4) How to confirm ECM side plug is fine, Can resistance be measured between pins to confirm? 5) Could it be fuel injector problem? How to narrow down it further? I had been to multiple mechanics but no success, everyone does something or other but problem isnt solved. Any help is appreciated ? Thanks Arvin
#2
10-08-2023, 12:50 PM
P0354 is a general code that can have causes other than the ign system.
The ECM function for the ign coils is to switch them on and off to cause them to fire. Each coil has a common 12V DC connection, common wiring to a chassis ground point and a common wire to send a signal each coil generates that it has fired which goes back to the ECM. If the ECM states to fire the coil and the coil does not send back a signal stating it has fired a code can be set.Assume one is not attaching say 120V or running the ign high voltage wire to the wiring connection on the coil, etc:
1) Can bad ECM damage ignition coil -assuming ignition coils were new? Doubt it.
2) Can bad ignition coil damage ECM? Doubt it.
3) The low tech way to check coil is to swap coil locations and determine if the code changes. There is a code for each coil location. Toyota also have test specs such as ohm resistance.
4) How to confirm ECM side plug is fine, can resistance be measured between pins to confirm? Yes and typically its checking voltage at certain pins at the ECM.
Could it be fuel injector problem? Yes. One can use a decent OBDII scanner to view real time data. If bad injector the code will stay with that injector and not move around when moving a ign coil when testing that coil.
Other causes can be engine air intake leaks, loss electrical connection, bad ECM.
If you have gone to various mechanics suggest you regroup and establish a plan of attack.
Given the extent of these issues and your questions suggest you find Toyota service info on the ign system, wiring and each code. Toyota has a website were for $25 one can download service info on Toyota products. Or buy a set of manuals or a DVD on Ebay.
Each code has its own detailed information page with explanation of code, what can cause it, what it takes to set the trouble code (what signals the ECM is looking or not getting) and how do diagnosis the code.
It would help to obtain a wiring diagram. The coil electrical terminals are ganged in terms of each getting its 12V DC from a common wire, each being grounded to chassis via a common wire and having the signal return output sent to the ECM via a common wire. A bad wiring connection can cause random problems and codes. Each coil has its own electrical terminal that runs separately to the ECM to tell the coil when to fire.
See private message.
The ECM function for the ign coils is to switch them on and off to cause them to fire. Each coil has a common 12V DC connection, common wiring to a chassis ground point and a common wire to send a signal each coil generates that it has fired which goes back to the ECM. If the ECM states to fire the coil and the coil does not send back a signal stating it has fired a code can be set.Assume one is not attaching say 120V or running the ign high voltage wire to the wiring connection on the coil, etc:
1) Can bad ECM damage ignition coil -assuming ignition coils were new? Doubt it.
2) Can bad ignition coil damage ECM? Doubt it.
3) The low tech way to check coil is to swap coil locations and determine if the code changes. There is a code for each coil location. Toyota also have test specs such as ohm resistance.
4) How to confirm ECM side plug is fine, can resistance be measured between pins to confirm? Yes and typically its checking voltage at certain pins at the ECM.
Could it be fuel injector problem? Yes. One can use a decent OBDII scanner to view real time data. If bad injector the code will stay with that injector and not move around when moving a ign coil when testing that coil.
Other causes can be engine air intake leaks, loss electrical connection, bad ECM.
If you have gone to various mechanics suggest you regroup and establish a plan of attack.
Given the extent of these issues and your questions suggest you find Toyota service info on the ign system, wiring and each code. Toyota has a website were for $25 one can download service info on Toyota products. Or buy a set of manuals or a DVD on Ebay.
Each code has its own detailed information page with explanation of code, what can cause it, what it takes to set the trouble code (what signals the ECM is looking or not getting) and how do diagnosis the code.
It would help to obtain a wiring diagram. The coil electrical terminals are ganged in terms of each getting its 12V DC from a common wire, each being grounded to chassis via a common wire and having the signal return output sent to the ECM via a common wire. A bad wiring connection can cause random problems and codes. Each coil has its own electrical terminal that runs separately to the ECM to tell the coil when to fire.
See private message.
#3
10-08-2023, 07:37 PM
P0354 is a general code that can have causes other than the ign system.
The ECM function for the ign coils is to switch them on and off to cause them to fire. Each coil has a common 12V DC connection, common wiring to a chassis ground point and a common wire to send a signal each coil generates that it has fired which goes back to the ECM. If the ECM states to fire the coil and the coil does not send back a signal stating it has fired a code can be set.Assume one is not attaching say 120V or running the ign high voltage wire to the wiring connection on the coil, etc:
1) Can bad ECM damage ignition coil -assuming ignition coils were new? Doubt it.
2) Can bad ignition coil damage ECM? Doubt it.
3) The low tech way to check coil is to swap coil locations and determine if the code changes. There is a code for each coil location. Toyota also have test specs such as ohm resistance.
4) How to confirm ECM side plug is fine, can resistance be measured between pins to confirm? Yes and typically its checking voltage at certain pins at the ECM.
Could it be fuel injector problem? Yes. One can use a decent OBDII scanner to view real time data. If bad injector the code will stay with that injector and not move around when moving a ign coil when testing that coil.
Other causes can be engine air intake leaks, loss electrical connection, bad ECM.
If you have gone to various mechanics suggest you regroup and establish a plan of attack.
Given the extent of these issues and your questions suggest you find Toyota service info on the ign system, wiring and each code. Toyota has a website were for $25 one can download service info on Toyota products. Or buy a set of manuals or a DVD on Ebay.
Each code has its own detailed information page with explanation of code, what can cause it, what it takes to set the trouble code (what signals the ECM is looking or not getting) and how do diagnosis the code.
It would help to obtain a wiring diagram. The coil electrical terminals are ganged in terms of each getting its 12V DC from a common wire, each being grounded to chassis via a common wire and having the signal return output sent to the ECM via a common wire. A bad wiring connection can cause random problems and codes. Each coil has its own electrical terminal that runs separately to the ECM to tell the coil when to fire.
See private message.
The ECM function for the ign coils is to switch them on and off to cause them to fire. Each coil has a common 12V DC connection, common wiring to a chassis ground point and a common wire to send a signal each coil generates that it has fired which goes back to the ECM. If the ECM states to fire the coil and the coil does not send back a signal stating it has fired a code can be set.Assume one is not attaching say 120V or running the ign high voltage wire to the wiring connection on the coil, etc:
1) Can bad ECM damage ignition coil -assuming ignition coils were new? Doubt it.
2) Can bad ignition coil damage ECM? Doubt it.
3) The low tech way to check coil is to swap coil locations and determine if the code changes. There is a code for each coil location. Toyota also have test specs such as ohm resistance.
4) How to confirm ECM side plug is fine, can resistance be measured between pins to confirm? Yes and typically its checking voltage at certain pins at the ECM.
Could it be fuel injector problem? Yes. One can use a decent OBDII scanner to view real time data. If bad injector the code will stay with that injector and not move around when moving a ign coil when testing that coil.
Other causes can be engine air intake leaks, loss electrical connection, bad ECM.
If you have gone to various mechanics suggest you regroup and establish a plan of attack.
Given the extent of these issues and your questions suggest you find Toyota service info on the ign system, wiring and each code. Toyota has a website were for $25 one can download service info on Toyota products. Or buy a set of manuals or a DVD on Ebay.
Each code has its own detailed information page with explanation of code, what can cause it, what it takes to set the trouble code (what signals the ECM is looking or not getting) and how do diagnosis the code.
It would help to obtain a wiring diagram. The coil electrical terminals are ganged in terms of each getting its 12V DC from a common wire, each being grounded to chassis via a common wire and having the signal return output sent to the ECM via a common wire. A bad wiring connection can cause random problems and codes. Each coil has its own electrical terminal that runs separately to the ECM to tell the coil when to fire.
See private message.
I am thinking if I can standalone check ignition coil then ignition coil itself could be ruled out, next it could be either ECM or Wiring harness or air engine leaks? Most of the mechanics I spoke to are hesitant to do resistance check for wiring harness integrity , so they just say replace ignition coil -> replace ECM together and if that doesnt help, we can replace wiring harness. I am bit skeptical on this blind approach, what if ECM was ok and wiring harness is problem or none of these are problem?
How likely it could be ECM or Wiring harness based on symptoms I described ? Thank you
#4
10-08-2023, 10:46 PM
As stated it is best to get as much technical info as possible up front then come up with a plan.
Toyota service info lists how to test the ign coils, what voltages should be a the ECM, etc. If you have a VOM meter you can check the ground, 12V power and return coil signal wiring and connections. One member here had a bad wire connection causing issues.
To check the ECU signals does require a on-scope or a decent scanner. Toyota uses Techtsream and the company supplied scan tool. One can get Techstream from third party sources and load it to a laptop or using a Bluetooth OBDII tool to a cell phone. You might review diagnostic software and scanner threads at the Toyotanation.com website.
As stated in the PM find the data for each code as this is will provide a diagnostic path.
Assume auto repair shops don't want to spend the time diagnosing an intermediate electrical issue as it can take a lot of time and they may not find the problem. The easy path is a new coil. Your situation is now beyond new coils and since no one will help you, you need to do it. I can tell you to check this or that but it's only a duplication of what Toyota has stated better and in more detail in their service info and info the list for each trouble code. As in Toyota states to check A, then B, then C, etc the LAST statement typically being if all is well to now then look at a bad ECU.
Toyota service info lists how to test the ign coils, what voltages should be a the ECM, etc. If you have a VOM meter you can check the ground, 12V power and return coil signal wiring and connections. One member here had a bad wire connection causing issues.
To check the ECU signals does require a on-scope or a decent scanner. Toyota uses Techtsream and the company supplied scan tool. One can get Techstream from third party sources and load it to a laptop or using a Bluetooth OBDII tool to a cell phone. You might review diagnostic software and scanner threads at the Toyotanation.com website.
As stated in the PM find the data for each code as this is will provide a diagnostic path.
Assume auto repair shops don't want to spend the time diagnosing an intermediate electrical issue as it can take a lot of time and they may not find the problem. The easy path is a new coil. Your situation is now beyond new coils and since no one will help you, you need to do it. I can tell you to check this or that but it's only a duplication of what Toyota has stated better and in more detail in their service info and info the list for each trouble code. As in Toyota states to check A, then B, then C, etc the LAST statement typically being if all is well to now then look at a bad ECU.
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