IS300h Hydraulic Noise when braking

[Macca99]

Hello All,

I have had my 2016 IS200h for 2 weeks now and have been hearing a hydraulic / hissing noise coming from under the bonnet (rear of engine bay on LHS) as car slows or brake is deployed at low speeds. It seems to be related to the braking (re-generation) but for the life of me I cant imagine this noise left the factory (or at least this loud).

Even when stationary, if I put the foot on the brake and remove, a second later the noise is heard.

Does this sound familiar to anyone? I will of course take back to the garage but would like to be in a knowledgeable position before being fobbed off....

 

[NemesisUK]

The regen braking  is inoperative at very low speeds. The car reverts to normal pads on discs.

Being a hybrid the braking system is pressurised by an electric pump. Might it be this you are hearing? Every time the mechanical brakes are used it depletes the reservoir pressure and once below the trigger pressure the electric pump cuts in to rebuild pressure. 

It's also very common for the brakes to groan slightly on application and release at very slow speed i.e. stop-start  traffic.

[Macca99]

Thanks for your help.

Of your diagnosis, I would lean more towards the electric pump, but would you expect it to so noisy.

From this forum I haven't seen any comments related to what I'm experiencing or even the electric pump.

Do you think the excessive noise be due to low fluid levels as I cant believe its on its last legs with just 20K miles on the clock?

 

[NemesisUK]

After only 2 weeks ownership I would take it back for a check, even just for peace of mind.

[darrude]

only noise I get from regen is the high pitched sound of the electric motor, but it sounds like that.  The only other nose is when the disc are corroded, you can hear the scraping of the rust on the first couple of times of use.