2001 Lexus ES300 Ignition Coil Resistance ??
 

Hello guys I know I need new ignition coils on my 2001 Lexus ES300 previous owner cheaped out and bought all Duralast coils with autolite plugs so i got stuck with the car running like crap now got rid of all the coils and plugs installed NGK plugs and pulled some coils off another Lexus at the junkyard all Denso but I think even those are bad I tested them with a multimeter on ohms setting and gave me some number like 343.3 ohms on all the coils read somewhere where the reading should be around 0.40-0.50 ?? I’m not sure let me know guys thanks

Should test less than an ohm, you sure your meter is working properly?

Hello yes it’s brand new ! I pulled the coil off faced electrical connecter side of coil towards me and has four male pins from left to right from left tested the first two pins on the coils and that’s what reading it gave me something like 343.3 or 343.4 ohm settings

Hello,

The problem is that those coils also contain igniters within them, so it will be tough to measure the resistance of coils themselves. A better way to test coils would be to get yourself a tester like this one and see how good is the spark on each coil. At least that is my understanding..

Hope this helps and best of luck!

This is from the 1997 Service Manual. Last time I measured mine I was getting 1.1Ohm for Primary Resistance while “cold” but my car runs okay. I wasn’t able to get the Secondary resistance readings because my probes couldn’t reach inside.


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Thanks for reply 97 had different ignition coils than 2001 no spark plug wire on this year if that resistance is right on a 97 than the 01 shouldn’t be that far off if so than these coils are really bad ! Measured resistance and was way high
343.4 cold ??! I pulled these out of another 2000 Lexus they looked pretty good but there probably burnt out

The problem is that a 1997 to 1998 used what's called a Wasted Spark System, meaning that it only had three coils for all six cylinders. That system still used a separate igniter, located somewhere near the Master Cylinder, which allowed coils to not have any circuitry directly in them. With that, in 1999, ES300 received a VVT-i system, and with it came a fully independent ignition with the igniters incorporated directly into the coils, so it will be a bit tougher to check coils with resistance than it was before..

Hope this helps and best of luck!

I knew about the wasted spark system on 97-98 but that other info is really interesting, thank you for sharing.

Thanks for the info guys I must have two sets of used coils from two 2000 Lexus ES
300 mine is 2001 today I started the car still misfire on all bank 2 doesn’t matter if I switch coils from bank 1 misfire still stays the same clear the codes same thing I tried starting the car and removing coils while running i can here the spark on 2 4 6 new ngk spark plugs so i had an old set of denso plugs took the coil off #6 inserted spark plug to see if I could see arc on the spark plug but could not see anything??? Getting spark to coil but no spark at the plug no matter which coil i use are the coils not sending strong enough spark ? Very frustrating I checked everything else all i can think of is these coils are bad ?? Don’t know stumped !!!

Next step is see if you are getting a signal to the coils, need a noid light or LED test light. Outside of the plug was grounded when you did the test, correct?

Wait so you tested for spark with old spark plugs? You should be testing with the existing spark plugs to reduce the amount of variables.

Also as noted, make sure the threads of the plug are touching metal on the engine to ground it during the test.

You mentioned you can hear the spark on 2, 4, and 6. What do you mean by that? How are you listening for spark?

What codes in particular do you have?

With no spark on all of Bank 2 the car won't start, so you should still have at least something.. If the plug wasn't grounded during your test, there is a high risk of frying the coil, since the voltage in it will keep increasing up until it would find a way to discharge the other way.

Below is the pinout for the coil, Pins 1 and 4 are for constant 12V and Ground, Pin 2 should supply power to the coil only when the ignition is in the ON position, while Pin 3 shuts off the Ground supply to actually ignite the spark, so that would be a pin to check on each coil. As LeX2K pointed out earlier, you will need to use a LED indicator for that, since a regular incandescent bulb won't have enough time to react.

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If the signal, as well as all the Power and Ground are present, then it would be time to look into other things, like sensor readouts and fuel trims, since coils are not the only ones that can give you a misfire, though it will require a scan tool with an ability to read engine live data.

P.S. Just in case, make sure not to drive or run the car for too long with a misfire, since it can vaporize your catalysts. The CEL starts to flash if the car detects a chance of catalysts overheating, at which point you should shut the car off and let it sit until the cats cool down.

Hope this helps and best of luck!