I've been working through numerous issues on my Lexus GS450h. One of the items that needed to be replaced was the Brake Actuator. I purchased the part new from a Lexus dealership, and had it installed by an independent Lexus shop.

That said, I now hear a "chirp" from under the hood when I apply pressure to the brake pedal. It sounds like a burst of fluid flowing through a valve. My question is that sound normal? Does it indicate a problem? This shop has been extremely difficult to deal with, and I honestly don't trust them at this point. Curious if this indicates a problem.

 

I would take it to the dealer and have them diagnose it properly. I had ABS module / Brake Actuator go out on my 460, they are similar to the 450h. But I did it the other way around. Bought OEM elsewhere but paid the Lexus dealer to install / program it professionally.




Make sure you use Toyota DOT 3 fluid. DOT 4 absorbs more moisture from the atmosphere, and get a new brake fluid cap, it helps keep moisture out, which is bad for the brake Actuator.

 

Did they use a scan tool to bleed the abs module? The scan tool manually activates the ABS module by following a specific bleed sequence to push out air. If just a normal brake bleed was done, then you might have air in the ABS module, which could be causing the noise.