Quote:
Originally Posted by Jim_in_Calgary
SOLVED - PARKING BRAKE MALFUNCTION CODE!
I did this job and got the dreaded parking brake malfunction code. I couldn’t find any solution on the internet to this other than take it to the dealership and have the code cleared. Now I followed this post to the letter and only made the mistake of unlocking the doors while I had an the Electronic Parking Brake ("EMF") wiring harness at the caliper disconnected. I thought this was the reason for the code. I even bought the “Carly for BMW” code reader and wifi/obd dongle, and paid for the $50 App. It couldn’t clear the code.
Now this EMF motor is just like a window regulator or a 12v winch. Its connector is 3 prong – and I’m confident these 3 prongs carry the following circuits: 1. Motor retract ( 12v+)
2. Ground (12v-)
3. Motor extend (12v+) As I was trying to clear these codes, I kept hearing motion at the rear brakes and the codes would be reset and automatically re-triggered. As an F10 owner has likely noticed, every time you start the car, open the doors, lock the doors the ECU for the EMF will cycle its test sequence. It does it all the time. The fact I couldn’t clear the codes indicated there might be a physical problem present.
Anyhow, in thinking about what that test sequence would be, I reasoned that you would need to test the extend function and the retract function. You’d be testing for both continuity in each circuit (bad connections) and a lack of seizure in any direction (by measuring the ampacity of each of the two circuits when the test sequence is run).
Conclusion:
If you leave the EMF extend/retract gear bottomed out (by turning clockwise with your Torx T45 as described above – which is otherwise necessary to do this job), you will simulate a seizure on the retract cycle of the test sequence the ECU runs darned-near every time anything happens while the car is parked. That’s because with the gear bottomed-out/fully-retracted it would simulate a retract seizure in the retract test phase (for lack of a better description).
Solution:
1. While doing the job as a last step (or take the wheels off and separate the EMF motor and gear if you already have this code) and before marrying the black plastic EMF motor with the male gear to the caliper with the female gear:
a. after your newly loaded caliper is mounted over the rotor, using your T45 tool, simply measure the remaining rotational clearance between EMF/pads and the rotor with a view to placing the EMF’s extension halfway between parking brake fully applied and parking brake fully retracted; b. Do this by counting how many rotations of the EMF gear it takes to start applying brake pad clamping on the brake rotor. THEN BACK IT OFF BY ˝ AS MANY ROTATIONS AS YOU COUNTED. You can rotate the rotor about 10 to 15 degrees with no brakng force on the rotor due to the slop in the entire driveline. When you feel caliper drag on the rotor so that you can’t rotate it back/forth, you know you’re fully extended. For me it took 10 counter-clockwise quarter-rotations of the T45 tool to extend from EMF fully retracted bottomed-out (as described above) to create clamping force on pads to rotor. I then just backed-off 5 quarter-turns (clockwise) and married the black plastic electronic motor to the EMF extender in the caliper and re-installed the wheels. When I unlocked the doors I immediately heard the gear drive going backwards and forwards (the EMF test cycle was being run). The best part, the “Parking Brake Malfunction” notice in my dash was GONE! (No code reader/clearing necessary).
I really hope this helps someone and contributes to the community. Now you don’t have to take it to the dealership and have them electronically extend the EMF in between EMF test cycles to clear the code. Just saved $180 at the dealership. Ran the Carly for BMW and cleared all codes which couldn't be cleared before the EMF position was moved from bottomed-out retracted position.
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This post saved me a trip to the dealer. yesterday
