[Mlaw]

The internal switch retracts the motor just enough to free the brakes for you to drive the car.
The OBD tool retracts the motor all the way so it allows you to push the caliper piston as needed when fitting new disc/pads

Thank you for the information.
I was a bit concerned as the tool did not really seem to be working but I updated it online and now it does retract it as you can hear it doing so for a lot longer than when you manually apply the brake. And the LCD is giving me positive feedback as to what's going on rather than before where it was saying 'not supported' etc.
This is ideal as now I am a lot more confident everything is working so I can service the brakes.

It's an Ancel VD500 in case anyone else is interested. £40-odd off Amazon.

Thanks again,
Martin

 

[sayek]

Thank you for the information.
I was a bit concerned as the tool did not really seem to be working but I updated it online and now it does retract it as you can hear it doing so for a lot longer than when you manually apply the brake. And the LCD is giving me positive feedback as to what's going on rather than before where it was saying 'not supported' etc.
This is ideal as now I am a lot more confident everything is working so I can service the brakes.

It's an Ancel VD500 in case anyone else is interested. £40-odd off Amazon.

Thanks again,
Martin

I have gone for the OBDevelen route that is similar price. There are lots of online support how to use this. I recently registerered a new battery with OBDeleven

 

[johnwads]

Disclaimer: Use this information at your own risk. I am telling about my experience only, you are responsible for your own actions and how you use this information.

I figured out how to do a rear brake job on the B8 Audi (A5/S5) with electromechanical parking brake without using a vag com to retract the rear parking brake. I will not go in to how to replace the brake pads because there are already two good posts explaining how to replace the rear brake pads:

Pad & Rotor Change DIY
DIY Rear Brake Pads - AudiWorld Forums

I knew there had to be a way to retract the electromechanical parking brake without a vag-com. The electromechanical parking brake is a 12-volt motor that engages and retracts the rear brakes. To retract the rear wheel parking brake, you will need access to a 12-volt battery and two jumper wires. One of the jumper wires should have an insulated clip on the end so you do not short-circuit the wires. When you are looking at the caliper you will see the brake line and electric wire/connector going to the rear caliper. Disconnect the electric connector from the caliper. Inside the connector on the caliper side you will see two medal pins sticking up. Connect the two jumper wires to the 12 volt battery. Take the negative wire jumper and connect it to one of the pins on the caliper. Then take the positive wire and touch the other pin without touching the other jumper wire and causing a short. If the caliper piston starts to push out, stop!, reverse the jumper wires. You should hear the parking brake retract and the piston not move. Continue until the caliper piston starts to spin, stop! Now push the caliper piston back in with a brake tool, c-clamp, etc. Replace pads as you would normally. After all the brakes have been replaced. Pump brake pedal until you have a firm pedal. Check the brake fluid. Then turn on and off the electromechanical parking brake a few times and you should be good to go. Very simple!

Great idea - worked as expected (SQ5). One best practice I'd suggest is to set (engage) the parking brake with the switch in the car prior to performing this job and then again manually with your leads once you've completed your work. I followed this procedure on the passenger side but not the drivers - the drivers side was all the way "open" whereas the passenger was fully engaged - and triggered a parking brake malfunction fault once I was all buttoned up and went to move the car.

I'm not sure how it knew something was amiss and turning the brake on and off a few times did not initially resolve the fault (I also got a recurring audible warning and light indicating to me that I was driving around with the parking brake on). I also turned the car off and on without resolution to the fault. You could manually resolve this by setting the parking brake in the car then running the motor in the direction of brake engagement until you felt satisfied, or perhaps you'll get lucky like I did and after letting the car sit overnight, the car sorted itself out the next time I hopped in and engaged/disengaged the parking brake - the drivers side parking brake motor had not previously spun long enough to engage the brake when it was in the "engaged" mode, after the car sat overnight it simply ran the drivers side long enough to fully engage.

Good luck and thanks OP for putting this method out there.