JMK

Does anyone know how this function works or what causes it to be activated? I've had 2 incidents in my 2012 CTT where the brakes are suddenly applied without any warning and ACC was NOT engaged.
Under both circumstances there was no eminent danger or loss of traction. 1st time occurred on the freeway and second time on surface streets...

I'm beginning to think there's a SW malfunction or sensor issue on the car.

TIA.

J

RESP

Hey JMK,
Were you applying the brakes at all in the incidents?

If you weren't applying the brakes, you may be correct, software issue.

Good luck!

JMK

Did not apply the brakes in either event.

Mike in CA

Emergency brake assist works by interpreting how quickly and with what force the brakes are being applied. If it senses the driver is attempting an emergency stop without applying full brake pressure, it takes over and applies the brakes fully. Bottom line in your situation, though, is that if you are not touching the brake pedal, and the brakes are being applied anyway, you definitely have a problem.

JMK

FWIW, here's what I found out about "active safe" system from service.


"Although ACC may be switched on and off , at speeds > 20mph" Porsche
Active Safe" may still intervene. The Radar sensor is employed and several
different warnings used , up to an " Acute warning " that uses a strong brake
jolt to alert the driver to a possibly hazardous traffic situation.
" Active Safe " complete function and prewarnings can be switched on and
off independently".

Mike in CA

My apologies for focusing on the emergency brake assist part of your question and missing entirely your reference to Adaptive Cruise Control. As I guess you've discovered that adds other variables to the equation. I don't have ACC; but maybe it's sensitivity can be adjusted.

JMK

No worries Mike! I don't think anyone at service new about this new feature until they contacted an engineer at Porsche in Germany. It's easily deactivated on the dash in the settings menu. Hopefully, that will do the trick!

race3

JMK: I have the active cruise control with the pre-safe system activated. it works when it's supposed to... i've seen it. but if yours is not working at the right time, have it checked. it should be accompanied with a warning when it activates as well... it surprised me yesterday and did a brake jolt when the cars in front of me stopped quickly. surprisingly it only does it when the risk of collision is VERY near. i would have yours checked out. or try cleaning the front sensor, just to be sure.

steph280

Do you have some type or radar detector or laser jammer installed? Some have been known to interfere with LCA, but could be related to your issue.