EPB drains battery

[bombka]

Hello, recently I was facing parasitic drain of about 0.8A. After pluging in multimeter the readings weren't constant. It was spiking from 0.2A to max 0.8A. I ended up with taking my '09 Avensis to a car electrican and he found out the EPB is causing Battery draw. The EPB unit was replaced to a new one by previous owner which I personally know. When Battery is fully charged there is zero problem with the brake, after about 2-3 days when the Battery charge is dropping down I'm getting parking brake fault message, which dissappears in a few minutes of engine runtime (but the brake still works despite the message). I noticed two things:

1. My rear braking discs are not in the best condition. There is a visible wear and I think I need to replace them in few months. Maybe they're too thin already and EPB system is constantly trying to tighten the grip more which causes battery drain overnight?

2. Parking brake does not apply itself after shutting off the car. It was that way when the previous owner had the car. But after searching information about my problem I found out that there's not a yellow light on the right side of dashboard about autobrake OFF, despite that the brake does not apply (I believe without light Autobrake OFF light it should apply after shutting engine down). 

Now the unit is disconnected under the car, I'd rather have car without handbrake that car that I can't start in the morning.

I searched the forum, but didn't find a problem like this but maybe someone had similar issues before. I simply don't want to replace all things if I don't need right now.

 

Thanks :)

[Cessna]

I seem to remember reading on this forum that the early T27 cars like yours did not have the facility to automatically apply the parking brake when switching off the ignition. If that is true, your issue number 2 is not an issue at all, just how the early cars are.

[Fers]

I have latest T27 model (2018 manufacturing year), and mine does not apply electric hand brake at anypoint, except when manually engaging it.

And about your issue, there is possibility that:

• replacement EPB was aftermarket model, which can cause issues
• when installing it, it was not done properly, loose wire or something like that
• aging, moisture that deteriorated something in mainboard/wiring

[Guest]

On 9/6/2023 at 8:38 PM, Fers said:

I have latest T27 model (2018 manufacturing year), and mine does not apply electric hand brake at anypoint, except when manually engaging it.

 

That's odd, it should apply automatically.  There might be a way to enable this on the OBD scanner. I think I enabled this on mine, it's one of the options on there

[Willss]

I thought that all of the 2015 onwards (and probably before) avensis EPB automatically came on.  Mine certainly does! Maybe different markets have different specifications?  Be interested to hear if OP solved why theirs was causing Battery issues.

[Derek.w]

Just a wild guess have you tried holding the brake button in its on position with foot on brake pedal for 7 seconds to engage automatic brake on function when its placed in park.

Note it disangages EPB function if you hold down the brake button for around 7 seconds.

[2009joe]

13 hours ago, Derek.w said:

Just a wild guess have you tried holding the brake button in its on position with foot on brake pedal for 7 seconds to engage automatic brake on function when its placed in park.

Note it disangages EPB function if you hold down the brake button for around 7 seconds.

When I changed my rear break discs and pads that's what I did when I put my push button handbrake into service mode .it was still in service mode when I drove the car around to make sure I did not lose center point then when I was happy I stood on the breaks and put on the handbrake out of service mode .never any bother with it great job