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Discussion Starter · #1 · (Edited)
Hi guys,

I have a 2015 Spark EV with 50k miles that I bought used in 2018. Recently in July 2020 I failed my safety inspection. Everything seemed normal before I went for the test but since my other cars have manual old fashioned parking brakes and since there were no errors that testing the brakes before the inspection seemed unnecessary. If I place the car in Neutral and activate the e-brake I can still easily coast my car forward several meters forward with my foot. At that point the dash will chime and the red brake led will chime momentarily indicating service is required and then the car goes back to normal.

Using a Scantool LX scanner and Torque Pro shows no faults. I took off my rear wheel and noticed additional unfamiliar hardware on the top of the brake piston. I have replaced the parking brake on older Camry/Avalons however this looks like a very different beast altogether.
 

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It uses the inside of the rotors as a drum for the parking brake shoes. They can be adjusted just like any other drum brakes. As a side note, they are not emergency brakes.
 

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The parking brake shoes are inside the disk aka drum in hat style. The odd thing sticking off of the corner of the disk caliper is a vibration damper.
When you engage the electric parking brake do you hear the electric actuator make a humming /whining noise?
The actuator pulls two cables that go into the back of the hub and move the little brake shoes under the disk.
Despite the high tech nature of this set up I would start diag by simply listening for actuator movement.
Guesses on what is wrong:
  • actuator is failed
  • cable broken
 

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Discussion Starter · #4 · (Edited)
Thanks, when I activate the parking brake I certainly can hear the electric actuator. At first, I did not think I could investigate any further without obtaining an absurdly short T-25 Torx key/bit to remove what looks like two bolts that secure the vibration dampener. I am relieved to find that I was able to simply use a 13mm wrench on the top and 14mm on the bottom caliper bolts and the dampener stays attached to the bolt when removed.

I noticed that when I remove some of the plastic inside the wheel-wells and look upwards towards the trunk I see an electric actuator. Now that I removed the caliper and disc, hopefully I can investigate what is going on with the actual brake cable mechanism when a helper is operating the parking brake switch.
 

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Discussion Starter · #5 · (Edited)
Update,

So I removed the caliper, pads and the discs to get a better look, since this fully motorized Spark EV is quite a departure for me from 2000/2002 Toyota brake jobs, I accidentally popped the rear cylinders out of their boots. luckily I always place a large pan under my work area so no harm done. With a bit of bleeding, I re-seated the cylinders in the boots, then added more brake fluid and bleed a cup of fluid for good measure. It seems there is no easy way to activate the parking brake without having to tap the regular brakes. I have placed a 1-1/2 inch wood block in the calipers (2x4?) to prevent the popped cylinder incident again.(See Pic). I hope this isn't too bad for the brake system.

To answer the previous question, when I activate the parking brake I hear an actuator go on and off but I see zero movement of the brake shoes.

I see this ACDELCO 13501701 {#92258052} Parking Brake Control Module on Rock Auto.

Hub with 1-12 block.jpg

$200.00 seems reasonable but I hate to start swapping parts that are probably not easily returnable without some additional diags or troubleshooting.

170896


-Pete
 

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Discussion Starter · #6 · (Edited)
Hey guys,

I ended up pulling the rear cover that covers the underbelly where the exhaust would normally be on an ICE Spark.
I found that the electronic actuator had somehow become disconnected from the right (and left) brakes themselves. I don't know how this could have happened or how I got through the last two inspections with the parking park in such a state but it is what is is.

I referenced my friends AllData to inch the brake cables closer and closer using the non-scantool method until I was able to hook things back together: (See Below)

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Electronic Parking Brake Cable Tensioning

With Scan Tool - Preferred Method

Block the drive wheels.
Install a Scan Tool to the vehicle.
Place the power button in Service Only Mode.
Select Configuration/Reset Functions from the electronic parking brake control module menu.
Perform the Parking Brake Calibration procedure.
Without Scan Tool - Optional Method

Block the drive wheels.
Place the power button in Service Only Mode.
Apply the brake pedal.
Place the transmission in PARK.
Momentarily lift then release the EPB switch to apply the EPB.
Momentarily press down then release the EPB switch to release the EPB.
Repeat step 5 and 6 to cycle the EPB on then off an additional 4 times.
The EPB module will be calibrated and proper tension will be applied to the parking brake cables.
 

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