brake pressure sensor

cr_craig
Posts: 18
Joined: Thu Dec 14, 2006 7:19 pm
Location: San Jose, CA

brake pressure sensor

Postby cr_craig » Tue Apr 26, 2011 9:39 pm

I've had a race-tech-supplied brake pressure sensor installed in the car for a couple of years, working fine. Recently relocated the DL1 and associated wiring, reconnected the sensor and only get voltages from 0.005 to 0.021 no matter how hard I stand on the pedal. As noted in my post concerning the red wire affecting idle, the DL1 is supplying good ref voltage and so on. Am I missing the pull-up resistor (which it's not clear is required with this sensor)?

osborni
Posts: 497
Joined: Fri Dec 07, 2007 9:08 pm
Location: USA, Michigan

Postby osborni » Wed Apr 27, 2011 12:12 pm

Not familiar with the Bosch sensors, but they should not need a pull up resistor. Try putting a volt meter on the sensor to see what output voltage you get when at rest and with the brakes on.

Of note is that the supply current from the DL1 is only 50 mA. The pressure sensor is speced at ~20mA. Have you added up the current draws from your sensors?
BMW 2000 M Coupe

cr_craig
Posts: 18
Joined: Thu Dec 14, 2006 7:19 pm
Location: San Jose, CA

Postby cr_craig » Fri Apr 29, 2011 6:57 pm

Okay, I get 0 V with brakes on or off. Cable or sensor must be broken. Bleh.

osborni
Posts: 497
Joined: Fri Dec 07, 2007 9:08 pm
Location: USA, Michigan

Postby osborni » Fri Apr 29, 2011 7:28 pm

Test is on the bench? I've bastardized a computer power supply for a cheep benchtop supply of good power and use an air compressor to test out pressure sensors....

Could be the wire or the sensor....
BMW 2000 M Coupe


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