ABS unit noise after initial start-up.

[skid2964]

My ABS light is on and the unit makes a strange low-tone buzzing noise after the car is started. it appears to have plenty of fluid in it. What could cause this?

- 1995 Honda Accord EX w/4cyl.

[jeffcoslacker]

Buzz is usually the ABS pump charging the accumulator. If it does it when you start it, I'd think it was bleeding off or dumping accumulator pressure while sitting, for some reason. Sorry, I have no idea why that would be.

Have the hood up when you start it, and watch the fluid in the resevoir. If the accumulator is charging, the fluid level should drop slowly until the pump stops.

If not the pump, you're hearing some kind of relay chatter or something.

[jeffcoslacker]

I was just thinking, I'm not sure how similar the ABS systems are from Honda to GM (all I'm used to working with), but if the light is on all the time, it may mean the accumulator is blown or an outlet valve is stuck, not holding pressure, and the pump runs until it sees no pressure is being built, then shuts off and sets the ABS light.

In any case, your brakes will work normally, you just may not have ABS function. You might wanna try to lock up the wheels, on some gravel or something, and see if the ABS is funtioning or not. Plus forcing it to operate might might clear the problem up if it is something like a stuck valve.

Have you ever had the brake fluid flushed? It's important on ABS systems, because moisture builds up in the fluid and starts to corrode valves and spools in the system, causing weird problems. (like you might be having)

[AccordCodger]

My ABS made the same noise. I ignored it and the ABS still seemed to work fine (and, by the way, it still did it after a brake system flush).

[jeffcoslacker]

Originally Posted by AccordCodger

My ABS made the same noise. I ignored it and the ABS still seemed to work fine (and, by the way, it still did it after a brake system flush).

You had no warning light though?

My Chevy's ABS actuator chatters sometimes when you first start it. Always has, since new.

[whoodie]

Same problem here, no apparant malfunction though. I Guess it's normal

[supercoup8]

Originally Posted by skid2964

My ABS light is on and the unit makes a strange low-tone buzzing noise after the car is started. it appears to have plenty of fluid in it. What could cause this?

- 1995 Honda Accord EX w/4cyl.

The abs pump needs to be bled. there is a bleeder near the fluid fill. open it, start the car,then shut it. The light should go out. You may have to do it a couple of times. Refill the unit.

[supercoup8]

Originally Posted by jeffcoslacker

You had no warning light though?

My Chevy's ABS actuator chatters sometimes when you first start it. Always has, since new.

He has to bleed the unit to get the light out