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Brake Pedal Position Switch and its usage in an aftermarket ECU

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Hi all,

I am in the process of making a patch wiring harness for my car and I came up to a brake pedal position switch my car has.

I want to keep things simple by removing what is not required and I would appreciate any input you might have on how this signal can be used with an aftermarket ECU.

Thank you in advance.


On the factory ECU it was probably used for Cruise Control. Here are things I could think of that might want to know brake status:

- Cruise Control

- Logging (although pressure is more useful for driver training)

- Brake Light control (I actually do this on my race car, but using brake pressure to trigger the lights)

- Transmission Torque management.

- Control of an auxiliary vacuum pump for power brakes.

Thanks for the input David.

My car is a manual and did not come with a cruise control for my MY/market. Other areas/newer cars did have it so I think Honda was thinking ahead.

Maybe even to raise the idle speed to compensate for alternator drag...

There is also no aux pump for my brakes.

In regards to your brake light control on your race car, I assume you do not send that input to your ECU.

So what I gather is that in an aftermarket ECU, like the Link G4+, there would not be any actual use for it and it would just occupy an I/O.

I used it for throttle blip on a customer's car, together with clutch input.

If your car has a clutch pedal switch (ideally one that triggers when the pedal is first pressed) you should wire it in for future use such as no lift shift.

Thank you Christoph!

My Honda S2000 is equipped with a cable TB, so I have to do rev matching manually! ;-)

The no lift shift idea is worth a bit more researching on my application though!

Could use it for antilag logic or burnout lockout solenoid interlocking to avoid additional switchgear in the cabin.

Thank you very much Michael, both are very good ideas.

Will not be implementing them to my car as it is NA and the diff is made out glass, but good to know for other cars.