ABS noise at startup

[tomd]

Dealer tells me its normal on startup to hear ABS noise as system does a self test. I can't imagine that this should happen every time key is switched on and you start to move. Any similar experience?

 

[Ken]

It does make noise for a few seconds each time you turn on the ignition. It is a self-test of the system, nothing to be alarmed about. :cool

 

[Tuna]

In my 92, the ABS makes a buzzing noise as it does its self-test when I start to drive off (forward or backward). It does it every time the car is started and moved. It's normal.

I read somewhere that the self test happens at 4 MPH. It appears so with my car.

Since the ABS control box is in the compartment behind the drivers seat, it's very noticable. In the C5 and other ABS cars I've had, the control box is mounted farther away from the driver and much less noticable. It almost impossible to notice in my 99 Buick GS but it's there.

 

[tomd]

Thanks to everyone for the help.

 

[Hib Halverson]

Dealer tells me its normal on startup to hear ABS noise as system does a self test. I can't imagine that this should happen every time key is switched on and you start to move. Any similar experience?

It is not normal to hear ABS "noise" upon starting the car.

It is normal to hear ABS noise (the ABS controller enabling its self-test) just as the car begins to roll forward the first time after a start-up.

 

[Radar]

Totally NORMAL. My 89 makes an ABS noise whenever I first move it after the car has been off. This is true whether I am backing out or driving forward after about moving 10 feet. This is the ABS calibrating itself. This is normal for the older versions of the ABS. I don't think the newer cars do this, but for sure the older ones do.

Hope this helps,
Bob (Radar)

 

[HPG]

Yep, my 88 does it each startup. If you have your foot on the brake, you can feel a pulse.

 

[CyberFire 12]

speaking of ABS

My SERVICE ABS warning light came on. I took it to a shop and they diagnosed it as a bad controller. I was quoted a parts price of $1250 plus two hours labor.

My questions: Is there a way to get a less expensive part? Is this a simple plug-in that I could attempt? My skills are limited and what equipment do I need?

I also have the INFL REST light on. That also was diagnosed as a bad controller ($895 part).

The shop has a good reputation but I am wondering what other options I have before dropping some serious bucks on this.

FWIW, I'm a firm believer in ABS, so I want to get it repaired.

Thanks.

 

[c4cruiser]

CyberFire 12-- Autozone shows a list price of $407 plus a $122 core charge for the ABS controller. Go to www.zutozone.com and click on the "Shopping" link and follow the process. Unless you are familiar with brake work, you may want to have a competent shop do the install for you. Given that price quote, I would try a "second opinion" at another shop. Make sure that the shop uses the appropriate module on a code reader to pull brake codes.

The INFL REST light is a fairly common problem with 1990 cars. It is usually a bad ground where the air bag sensor attaches to the frame. There is one on each side of the car; below the battery on the left and below the A/C and heater box on the right. This is a fairly simple thing to fix. Disconnect the battery and wait for at least 10 minutes before touching the sensors. While you're waiting, jack up the front of the car and remove both front wheels (just need working room here). On both sides, remove the back half of the inner fender panels.

On the left side, remove the battery and tray (you won't need to remove the gill panel). The sensor is a small box bolted to the frame. Remove the two bolts holding it to the frame and use a wire brush or sandpaper to throughly clean the rust from the frame and the bottom of the tab on the sensor. Apply some dielectric grease and reattach the sensor.

On the right side, do the same thing. There is not a lot of room to unbolt the sensor here, so small hands will help but it just takes some time to do. On a friend's car, we covered the sensor with a rubber sheet after cleaning everthing. Condensation from the A/C above drips down on the sensor and causes the rust. Most of the INFL REST problems come from the right side sensor ground.

Once that is done put everything back together and reconnect the battery. The INFL REST light may or may not go out. There is a procedure to reset the light here:
http://corvetteforum.com/techtips/viewsubtopic.php?SubTopicID=46&TopicID=2

Good luck!!

 

[HallenTi]

You will find that the self-test occurs at about 4 MPH when first moved in either direction. It is normal, but I admit to wondering myself before I found out.