AA--Sounds very much like your ABS module is going. The sound you hear is probably the ABS pump cycling because of the faulty module. It goes through a little check every time you start the car, and when the module is faulty you hear this weird noise coming from the pump, which is under the hood next to the module.
DON'T take your car to a dealer to replace the module. They will stiff you six to eight hundred, depending on what they think you're worth. Take the module off and send it to Victor Roche. Look him up on the net. You have to send him an email to get his address, telling him that you have a Volvo with a shot ABS module and he will email you back his mailing address. It will cost you about $135 plus postage to have Victor fix it. If you take it in to Volvo and they fix it, they will install a new one and it will fail again. Victor's fix is permanent. The ABS module is made in the Philippines or some such place, is used on a lot of different European cars, fails regularly since it was introduced about ten or twelve years ago, and is a cash cow for service departments.
The ABS module is located beneath the brake fluid reservoir, a square black piece of plastic about three by four inches and one inch deep. It is held in place by four corner screws whose heads takes an E5 socket. This is a female Torx socket, not male. There are E6 Torx sockets all over the place, but the E5 is hard to find. Slip a piece of cardboard or plastic under the car below the ABS module because the chances of fumbling one of those long screws and dropping it down into the engine compartment (you're lucky if it makes it to the ground) is great. Disconnect the battery first BEFORE taking out the module. It's a witch getting those four screws out because you can't see them--they're on the bottom side of the module. It's a real feel and fumble operation. Once you get it out DON'T open it up. Doing so apparently causes diagnostic problems for Victor. He says as much in the email he sends you, along with his address. Once you remove the module your speedometer needle won't work. Not a biggy. You will have standard brakes but obviously not ABS. Victor is very fast in sending the module back because of the above. Turn around is often just three days--day down (if you send overnight) day there day back.
Hope this makes your weekend for you. Dick
|