No.

You can safely use 2004-2005 coil packs on an ap1.

 

Thanks!

 

It's a little confusing... cuz, correct me if I'm wrong, but when ordering the 04-05, you may get the one with the R mark (resistor) and also the little raised-squares/ribs.

 

This is my interpretation of the OEM service manual page posted above:

Do not use 2000-2003 or 2004-2005 coil packs in a 2006-2009 S2000, or those coil packs will be damaged.

It does not state that the R-coil cannot be used in other models.

 

I tested my 4 original coils and the 1 new one with a multimeter.

With the meter set to 2000Ω, I got a reading for each old coil (in no particular order) at 1190, 1190, 1194, 1195. <shrug> They are probably completely fine, seeing as not one of them measured significantly higher.

What's interesting is that the NEW coil measured 1070. Which I guess means less resistance, and therefore bigger spark, and therefore I just modded one of my cylinders? Sweet.

 

I dont want the ECU trying to mess with ignition and throttle inputs when it is not getting proper air, fuel or ignition inputs or control. That seems pretty logical in my engineering brain. There is a ton of safety related items that go into firmware for regulated industries like automotive, medical, etc. And part of that is being able to show no single source of failure among other things. So having the FW make control decisions that over ride the the users input (Aka traction or stability control) while having known questionable inputs on the key items that this effects is a huge no no. So this falls right into line with the typical I have seen.

 

Don't forget aviation. We had an A330 takeoff out of AMS to the States after the plane was polished and cleaned in a hanger there in the Netherlands. Some polishing compound was missed plugging a bit of one of the three pitot tubes. Failures began just before liftoff and continued. Fortunately the weather was nice so the plane could return to Amsterdam. The issue was the cascade of failures from that one erroneous output. It was a big deal with Airbus, the company, pilots and the FAA to get to the bottom of it and fix it. This happened before Air France sent an A330 with iced up pitot tubes into the Atlantic.

I can see how your engineering brain sees exactly this type of problem. Me too.

 

On second thought, this seems like a huge liability for Toyota. If customers were to crash due to wheel spin or anything traction related and it was found that their cars disabled traction control due to a, for arguments sake, secondary air injection solenoid fault then, won't a lawsuit ensue based on the fact that the drivers did not deactivate traction control rather their cars did so as programmed by the manufacturer? At the very least the insurance companies might go to town refuting claims on this basis...

 

Interesting indeed! Sounds like you have a nice job

Moral of the story: attention to detail is of critical importance.

 

The S2000 operates the same way.