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153 Posts
Discussion Starter · #1 ·
Hi Everyone,
I have a Bosch iBooster and the brake pedal from a 2014 Model S p85.
I'm wiring them into my jag and would like to double check from anyone who might no better than me.

Some details
The brake switch has four wires
There is continuity between one red/white and the white/green when the switch IS pressed, but not between any other wires.
There is continuity between one red/white and the green/purple when the switch is NOT pressed, but not between any other wires.

My summary is;
white/green - Brake on
red/white - power ??
red/white - power??
green/purple - brake off

The iBooster has lots of wires;
fat yellow - power
fat black - earth
red/yellow - ignition or brake switch?? (notice this wire branches into 2)
red/white - brake switch or ignition?? (notice this wire branches into 2)

optional wires
couple of CAN twisted pairs.
two black wires that go to a plug in the fluid reservoir. I'm thinking they control a light to the dash to warn you that the fluid is low.

DrJeff confirmed the ibooster wiring except for the red/white wires that i have.

My assumption is that the red/white on the ibooster goes to the red/white on the brake switch as they are the same colours. is that a reasonable guess?
I therefore think the red/yellow is ignition.


113 Posts
Hi, is this section still alive?

I got an ibooster, which I believe is the newer generation. (See attached)
I followed this amazing article - Wiring the Tesla iBooster - EVcreate, but cannot get it to run. Running it off the 12VDC car battery. Pin#1 bat+;
pin#9 com/bat-;
pin #20 bat+
Mine looks like gen2, but doesn't have a brake fluid reservoir cap.
Any suggestions?


113 Posts
Thanks for replying.
Glad to hear my blogpost was helpful.
Did you also wire the pedal travel sensor?
I only see three wires connected to the ECU.
On the GEN2 you have you need (at least) 7 wires to/from the ECU.
From what donor car is it?
This is from MX.

I've only wired the power requirements, ignition signal and then pushed the pedal initiator. Didn't get any movement.

113 Posts
Yes, like that.
Think it makes the ECU more universal.
GEN1 had an external sensor so in that case it was really needed to wire externally as well.
Ahh, brilliant! It's alive! :) Thank you.
Question. When I power the ibooster without ignition (pins 1 & 9, nothing on pin 20 = open) it doesn't assist the brake. Then I simulate ignition (pin 20 = +12v), ibooster does brake assist. Then I disconnect ignition (pin 20 = open), it still brake assists until complete power off.
Should the ignition signal be tied to ground when off (pin 20 = gnd)?
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