I learned this test a few years ago. I continue to be amazed by how many technicians I talk to that want to replace all of the coils on the Nissan V6's for the P1320 codes. Now I understand that some Maximas have updated coils to address this code and the TSB says replace all 6. This is usually a hard sale to a customer that has a car that runs fine. This test works on all COP Nissan and Infiniti models.

Hook up you scope to the Power Transistor wire at each coil. Scale is not too important since you are pretty much looking for the odd man out. You do probably want to be set under 20v though since the signal is about 0-4v. You should get a pattern similar to this on the good coils [2002 Nissan Pathfinder LE, Ignition Waveform]. This is a known bad coil but the patterns tend to vary on the bad coils. [2002 Nissan Pathfinder LE, Ignition Waveform]. The idea is to look for the coil or coils that have a different pattern. I have fixed at least 20 cars successfully without replacing the entire set of coils so far.

If the pattern on each coil is the same you will need to look closely at the pattern. If you have a nice square wave with little or no ramp up you probably have the wrong spark plugs installed. Bosch Platinum plugs will give you a pattern that looks exactly like a bad coil.

I know that this code has been the cause of quite a few comebacks for a lot of people so I thought that I would share this tip.

Todd from Georgia

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