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Randall C
Randall C, ASE Master Tech
Category: Mazda
Satisfied Customers: 12803
Experience:  ASE Master Certified, 35 yrs, Diag/Electrical Specialist
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2004 Mazda 6 2.3L No spark from coil tower Cylinder#1 and #4

Customer Question

2004 Mazda 6 2.3L No spark from coil tower Cylinder#1 and #4 The Blk/Wht lead to coil pack has power does not blink when cranking or running. KOEO test first was faulty intake manifold shutter selenoid ..that has been repaired need spark from coil on 1 and 4 coil already replaced
Submitted: 7 months ago.
Category: Mazda
Expert:  Randall C replied 7 months ago.

Hello, I am Randall. I am going to say about 99% you have a bad PCM. The PCM triggers cylinders 1/4 as a pair and 2/3 as a pair, 2/3 are working so the signal from the PCM is not being provided to fire 1/4. There are 2 wires to the PCM, They are at terminals 1A and 1B. If all wiring is ok? you can switch wires 1A and 1B and then 1/4 should fire and 2/3 will not, this confirms failed PCM. here is the link to the wiring diagram showing these wires and terminal locations

Please rate my service I have provided today, Thanks,Randall