29 September 2021

This Is The Stupid

The sensor is supposed to show 1k to 4k across its entire range.

The arm should rest at 3.1k and signal the brakes being applied at 2.9k.

My sensor reads 937 to 3,630 ohms across the range.

With the arm at the rest position it reads ≈2.8k and ≈2.6k with the pedal pressed.  My rest resistance is below the expected brakes-on resistance, so the BCM thinks the pedal is pressed at rest.

If I had a Tech-2 or equivalent I could run the calibration routine and see if it would resume working.

I have to cajole JT into using his.


  1. Add a 100 Ohm resistor in serial with your sensor?

  2. After looking at that again you might need a 330 Ohm resistor. That should make it read between approximately 1267 to 3960 across the range, and about 3k in rest and 2.9k brakes applied. Might be close enough to work.

  3. It used to work and now it doesn't. That means the potentiometer value changed and it may change further as time goes on. We're assuming the 4 month old part was from a bad batch and will try to warranty it. Since it's $15 part and takes 10 minutes to install now he's discovered the secret, he'll change it out and hopefully be done with it for a few years. It is a stupid design to have a variable resistor moving over the same 5 degrees of travel dozens if not hundreds of times a day when a simple switch would do the job.


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