2000 Camry/Solara Brake Booster??
 

I have a 2000 Toyota Solara with 280,000 miles on it. Car still runs great and body is starting to fail, but it is worth keeping up on. Recently done are all 4 wheels with new brake pads and rotors. I have always noticed since I have had the car that I cant lock up brakes in emergency situation. Slamming on the pedal, it wont lock up but stops fairly quickly. The Problem..... Check engine light came on trac light also. Checked codes and have PO171, and PO420. Tried cleaning mass air flow system and cleaned/replaced air filter with no result. Now the brake light keeps coming on and i have to add a little fluid for it to go off. I have pulled all 4 tires and checked everything and cannot find a brake fluid leak anywhere. Had into buddies garage for oil change and I told him to check the check engine light. He came backwith:
Diagnose ses light on code Po171 and PO420 in memory. Vacuum leak in power brake booster causing PO171 further testing post Po171 repair for Po420. Estimate of $700 to replace booster.

Could this be where my brake fluid is dissapearing too?
Could it just be that exterior check valve?
Could this be why I cant lock up brakes?
It doesnt look like too difficulta job to replace booster myself i Think.

Any opinions or help would be appreciated Thanks Andy

The booster is separate from the master cylinder. It is possible the master cylinder is leaking brake fluid into the booster and may have caused the booster diaphragm to fail.

Brake fluid may now be being drawn into the engine through the vacuum hose connected to the engine. Disconnect hose from the booster and check for signs for brake fluid.

The now leaking brake booster (leaking both air and fluid) may also be causing the engine to have a lean mixture. The result being P0171.

The P0420 code is for the converter operating below efficiency. This is typically the converter itself (which may have failed due to brake fluid) or a bad 02 sensor.

If the car has traction control, this is antilock braking. The purpose is to prevent locking of the brakes.

Replacing the booster should be straight forward. Pickup some service date to reference and search the internet for possible posts, YouTube videos on how to do this.

The other issue is the master brake cylinder which may need replacing.

Once these repairs are done. Have the codes cleared or drive long enough and enough times to determine if the check light goes off. If the repairs fixed the problem the computer will reset after a number of drives.

However P0171 is typically linked to a failing O2 sensor. Which can also be a reason for the P0420. Or it could be a bad sensor and converter.

The Trac light will come on with the check light. There may not be a problem with the braking system other then the possible master cylinder and brake booster.

Start with the booster and check master cylinder. Then determine what happens with the trouble codes.

Sorry it took so long to respond but the site wouldnt let me sign on. Long story.
OK, replaced brake booster and master cylinder, not to difficult a job, but when i pressed on the brakes I found a leak in the rear brake lines, I think thats where I was losing my brake fluid. Because when I pulled master cylinder from booster, it was dry, but replaced both anyways.
Had brake lines replaced and power bled, and the brakes work like they are brand new!!
Cleared the codes and drove for a week or so and light came back on, checked and p0170 code is gone, just the P0420 is still there.
Had them look at loud exhaust,and the only thing wrong is rusted out flanges where rear pipe ties to muffler. there is a 90 degree piece of pipe coming out of the inlet of muffler that ties to long pipe coming from front. Gonna try and get these flanges cut out and a piece of stainless welded in to repair. all the pipes are stainless and in good shape, we will see if this is causing P0420 code or not.
Will check back when completed with results.
Thanks for help so far, you were spot on!!!

Great job!

A leaking exhaust pipe before the converter can cause P0420.