Thumping noise from right front when first starting to drive off

Bobertsr · #1 (**permalink**) 04-03-2008, 12:27 PM

2006 Avalon Limited, 34K miles: I am starting to notice a "thumping" sound coming from the right front when I first start moving. Doesn't do it every time. 5 or 6 quick thumps not related to wheels turning, more engine turning, then it goes away completely. Seems to be right after vehicle has been parked for a while. I have had the intermediate steering shaft replaced which cured front end clicking. Thumping is unrelated to this. It's still in warranty but I want to be educated before I take this story to them. Any ideas? TSB? If so, whats the number? What I've read about ST002-06 seems more related to the clicking noise that is now gone. Thanks!

inov8 · #2 (**permalink**) 04-03-2008, 01:45 PM

If you park on an incline, and then let the car roll without starting the engine, do you still hear (or feel) the "thumps"? (be aware you will not have power steering or power brakes available when performing this test)

I assume if you start the engine, but do not actually move the car, the thump does not occur. When you hear the thump, can you feel anything, either in the steering wheel or brake pedal? Some cars ran a periodic ABS system diagnostics routine.

Quoted form the '05 Avalon features manual, page CH-49:
"After the ignition is turned ON, and the vehicle attains an approximate speed of 6 km/h (4 mph) or more, and only at first instance, the Skid Control ECU performs an initial check. The functions of each solenoid valve and pump motor in the brake actuator are checked in order."

Bobertsr · #3 (**permalink**) 04-03-2008, 07:48 PM

Well now, isn't this interesting! My car does not have TCS or VSC; however, I looked under the hood and low and behold, the ABS controller is sitting right there in the right front corner! This necessitated a scan of the Owner's Manual which states on page 267: "You may hear a click or motor sound in the engine compartment for a few seconds when the engine is started. This means that the Anti-Lock Brake System is in the self check mode, and does not indicate a malfunction."

Makes sense to me. Thanks, inov8!