I had the brake TSB done on my 2008 Auto HHR SS a few weeks ago. It made the brakes worse during cold start up! No doubt about it.

I took the car back to the dealer yesterday and they can't seem to find the problem. They told me "That's just something the automatics are going to do. You'll need to let it warm up."

WHAT?!?!?

Help! Any ideas? Suggestions?

Thanks!

 

Hmm..thats all Ive ever done....takes less then a minute

 

Take it somewhere else... I had the fix done on mine and it fixed the problem 100% on as soon as they were done.

 

I never really thought about it, but during cat warmup there is basically no vacuum. That must be the cause of this. If you wait just one minute, like previously stated, the ecu will decrease engine load and it will start drawing vacuum.

 

Exatly. Granted I have a post 1/09 built '09, but anytime I turn it on I let it go through the warmup cycle before I go anywhere. It takes about 60-90 seconds and to date I've no problems with the brakes. Since you had the TSB done try doing that and report back if it continues happening.

Later
Allex

 

What Ive been saying...turbo is spooled up on cold start...once turbo settles down the booster works....the real question is why the booster bleeds down so fast.

 

UPDATE: After one week and one day, the dealer discovered the ECM was bad. Brakes work great on cold start now.

No need to wait 60-90 seconds every time you get in the car. Have the TSB done and you will always have brakes.