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Chris (aka-Moose)
Chris (aka-Moose), Auto Technician
Category: Toyota
Satisfied Customers: 814
Experience:  16 years of experience
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Corolla: I have a corolla 99 model have no power to one coil

Customer Question

I have a corolla 99 model have no power to one coil pack need to know if coil packs are fused
Submitted: 1 year ago.
Category: Toyota
Expert:  Jan Andersson replied 1 year ago.
Hi, Yes and no. They are not individually fused, but there is a 15A fuse before the ignition switch that powers that circuit - BOTH coils at the same time. So if you have power to ONE, then the fuse and ignition switch are good. The power wire splices into the two coils after the ignition switch. (Black/white stripe going to each coil). Can you see where the splice is? My system doesn't show where, it shows what I think is a picture of the connector J11 where the splice is made
Customer: replied 1 year ago.
both black/white stripe wires have 12 volts on them with the ignition turned on , but coil to cyl. 2 & 3 still has no fire , I swapped coils to eliminate it being faulty, got same result , no fire on 2 & 3 ........?
Customer: replied 1 year ago.
what impulses the coil ?
Expert:  Jan Andersson replied 1 year ago.
The PCM sends a signal to energize the coil for "charging" it, then de-energizes to create the spark. When one energizes, the other one sparks and vice versa. (The yellow/green and red/light blue wires). Maybe its not sending the pulse to the other coil. You could check for pulses on each wire at the coil end, and then again at the PCM end, to make sure its not a wiring problem. just need to find the right wires. WHY it would trigger only one coil and not the other, I don't know. Could be a bad PCM.
Customer: replied 1 year ago.
after seeing that it only powered one coil I thought the pcm was the trouble earlier cause I have found no bad wiring , well , where is the pcm on this thing and how much dash board do I have to remove to get at it ?
Expert:  Jan Andersson replied 1 year ago.
Here's a blow-up diagram, I'm not sure if you have to remove ALL of the pictured parts. Its in the middle under the dash, forward of the shifter. A dealership would have a tool that can read the PCM outputs to see if something is not right.... going at it on your own would be time consuming, before digging in, I would call them and ask how much they would want for just the diagnosis part, and if they can do it if you bring the PCM to them. I understand the car is not driveable as is and towing comes at a cost too.

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