!!!!Electronic Parking Brake Malfunction!!! Workshop!

[moltuae]

Originally Posted by steamship

Maybe someone who can read current flow diagrams can assist. Here is the relevant diagram, and from it I can see that the two heavier wires go to the actual motor. Not sure about the other two.

There's not really any info there to read, except that the symbols imply that there is some electronics involved. The ECU terminals are marked S+/S- (as opposed to the M+/M- of the motor terminals), so my guess is 'S' stands for signal and that they provide some sort of feedback. It could be a serial data link (probably unlikely), PWM (possible) or a simple 0-5 volts signal. I'd start by putting a (DC) voltmeter across the wires to see how it changes. If that's inconclusive an oscilloscope should reveal what's going on.

The fact that there are only 2 'signal' wires would lead me to suspect that it's just a simple voltage/resistance measurement, anything more sophisticated would require a power connection too. While it's possible to send power and data over the same wire, I think it's rare to see that in automotive applications.