Can anyone tell me what the neutral switch does, and what is affected when unplugged or malfunctioning? It’s a little confusing what its functionality and usefulness is.
What is affected on the stock ECU if malfunctioning?
What is affected on the PFC if malfunctioning?

The neutral switch is a normally ON switch in the neutral position; meaning if it is unplugged/malfunctioning, there is no continuity in the circuit.

What repercussions are present, if malfunctioning?

Neutral switch can be found in the workshop manual on Page Z34

Anyone understand this system, and can pass on a little info please?

 

The neutral switch affects idle control for one. When you coast to a light, your idle will dip, and if you removed your coolant through your throttle body and your neutral switch is not functioning, you will have a very low and erractic idle until warmup.
I think that there is positive voltage on the neutral switch wire that goes into the ECU when in neutral position. The other pin on the switch goes to ground. If you have the service manual, there is a section in there on how to test the switch.

 

It will also deactivate cruise.

 

Hey thanks for responding guys. Simple system I know but surprisingly almost no information on this topic exists here for this car explaining in finer detail than what the manual gives.
I did find small snippets in the manual about those issues, but how do they affect a car that has been fitted with the PFC? Does the PFC mimic the stock ECU with respect to the neutral switch in every way? Or has the system been augmented in any way that changes its core functionality?

What are the repercussions of a malfunctioning (open circuit) neutral switch with the PFC

The point of my inquiry is that I plan to do a little research to see if I can “Safely” add a remote start to the car, without interrupting any of the stock systems.

My issue at the moment is that I need to somehow duplicate the state of the neutral switch with two independent circuits, one line to replace the neutral switch , and one to control the GO/NO GO functionality of the remote starting mechanism, but that does not require any parasitic draw to do so .

While two switches running off the same point would be ideal, it does not seem practical, so I am looking to either replace the neutral switch functionality with my own or come up with a clever way to augment the system.

 

I am not 100% sure but I would think that the PFC would also look at the neutral safety switch as does the cruise control module. You could possibly piggy-back the switch by using diodes to seperate the circuits.

 

FWIW, I added cruise to my R1 several years ago. I have since added a PFC and deleted emissions/AWS. I saw no change in cruise functioning. Everything is pretty normal.

 

mazda put it there for a reason, dony cut corners cause it bites you in the *** later