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Unfortunately not that simple. Its a 4 pin brake pedal position sensor. Its got some kind of potentiometer in it. It compares the brake pedal position with the ABS system brake pressure to allow a crank signal to proceed.
The other two wires are for the cruise control deactivation switch.
U = Blue B = Black
Last edited by McJag222; Aug 17, 2025 at 07:15 PM.
The other two wires are for the cruise control deactivation switch.
U = Blue B = Black
Wow. OK. Looks like the two center pins Blue and Black are normally open and the contacts close when the pedal is pressed. Not sure about the other two pins.
Wow. OK. Looks like the two center pins Blue and Black are normally open and the contacts close when the pedal is pressed. Not sure about the other two pins.
Brake - normally open - cruise normally closed - later model diagram:
first, thanks to everyone for providing so much input.
I got the car to start today by cheating the system. A hot wired fuse F-19 in the engine compartment fuse box and powered the solenoid for the starter directly while the ignition was on. It started right up.
Current situation:
1. The brake switch is fine. Both the old one and the new one. Brake lights work, the shifter shifts into gear when the brake pedal is depressed.
2. I would also test the starter solenoid (Relay 10) but I don't know where it is. It is shown on the engine compartment fuse box but I don't see it, unless it's buried inside under the first layer of fuses. Can this box be disassembled? I don't think my issue is the solenoid though.
2. When the brake pedal is depressed power from the switch goes to and splits off at CAS24 (I don't know where or what this is) all over the place into four different places including, the Central Junction Box, the parking brake module, the Auxiliary Junction Box (brake lights), and the ECM (to control the starter relay).
I'm still getting the same codes:
- U0415 Invalid Data received from ABS Control Module
- P0504 Brake Switch A/B Correlation
I'm starting to wonder if my parking brake fault which I've had for a long time is somehow related to all this.
Maybe time to start chasing wires all over the place.
first, thanks to everyone for providing so much input.
I got the car to start today by cheating the system. A hot wired fuse F-19 in the engine compartment fuse box and powered the solenoid for the starter directly while the ignition was on. It started right up.
Current situation:
1. The brake switch is fine. Both the old one and the new one. Brake lights work, the shifter shifts into gear when the brake pedal is depressed.
2. I would also test the starter solenoid (Relay 10) but I don't know where it is. It is shown on the engine compartment fuse box but I don't see it, unless it's buried inside under the first layer of fuses. Can this box be disassembled? I don't think my issue is the solenoid though.
2. When the brake pedal is depressed power from the switch goes to and splits off at CAS24 (I don't know where or what this is) all over the place into four different places including, the Central Junction Box, the parking brake module, the Auxiliary Junction Box (brake lights), and the ECM (to control the starter relay).
I'm still getting the same codes:
- U0415 Invalid Data received from ABS Control Module
- P0504 Brake Switch A/B Correlation
I'm starting to wonder if my parking brake fault which I've had for a long time is somehow related to all this.
Maybe time to start chasing wires all over the place.
go into the dsc module with a good scan tool and pull dtcs out of it, u0415 is their way of telling you go read dsc codes now.
i forgot all about cjb needing to recieve minimum pressure from the dsc unit (internal pressure sensor) over CAN to allow a crank request and send power to terminal 30 of the starter relay, PCM finishes the job by powering and grounding the relay coil.
it flat out does not need the brake switch to start, unlocking the shifter is a different story. i just unhooked it on a test car and it starts right up. brake lights will turn on with zero system pressure, starter activation happens at minimum 20 psi.
topdon topscan thinkdiag, autel ap200 are the cheapest that will let you do this
I don't think relay 10 is the problem. I think the ABS deserves more scrutiny as Xalty recommended. I think R10 is behind the power distribution box. Maybe a re-flash of the ABS module is in order.
