buzzer on braking in ML-270

[Mark A]

When I brake reasonably hard in town, I sometimes get a warning buzzer - but no lights on the dash to indicate a problem. The lights are working as they all go through the self test when the ignition is turned on. Is this a known problem as it's driving me nuts.

Cheers,
Mark

 

[panason1c]

There is a warning buzzer that sounds if you move off with the foot operated handbrake on........are you catching the handbrake with your foot when you brake?

Try moving off with the handbrake gently applied and see if it's the same warning buzzer....

 

[Mark A]

There is a warning buzzer that sounds if you move off with the foot operated handbrake on........are you catching the handbrake with your foot when you brake?

Try moving off with the handbrake gently applied and see if it's the same warning buzzer....

Unfortunately no, what I heard was a continuous buzzer sound. When I try the handbrake, it is a beeping sound. Thanks anyway.

Cheers,
Mark

 

[psmart]

Havent come across this problem, but it could possibly be your brake pads are worn to the limits and the sensor is making contact with the discs!

Pop your head under and look to see if there is any meat left on the pads.

 

[panason1c]

Just a thought.........check the brake master cylinder fluid level....it might be borderline low enough that when you brake hard the level shifts enough to activate the warning buzzer.......are you sure that there are no warning lights whenever the buzzer sounds?

 

[Mark A]

The first thing I did was to check the fluid level, and it seems to be at the max mark. I will get under it tonight and have a look at the pads. Sods law, it hasn't made the noise again on my 30mile trip into work this morning.

Will keep you all posted on the results.

Cheers,
Mark

 

[panason1c]

I will get under it tonight and have a look at the pads.

The pads 'worn sensor' only activates a warning light.........

The only reference to a buzzer sounding in my ML handbook relates to the EBV feature (Electronic brake force distribution).. the buzzer sounds when there is a fault within the system but also the ABS and BRAKE warning lights are activated as well...But you said that no lights appear so its a bit of a head scratcher!.

You will probably need to hook up to MB's Star machine to read off any logged codes.

 

[Blobcat]

Is the ABS kicking in and the noise of the ABS is what you are hearing?

 

[panason1c]

Is the ABS kicking in and the noise of the ABS is what you are hearing?

Good point!

 

[Mark A]

Is the ABS kicking in and the noise of the ABS is what you are hearing?

Buzzer when ABS kicks in ????? Is that what is supposed to happen ?

 

[panason1c]

Buzzer when ABS kicks in ????? Is that what is supposed to happen ?

I take blobcat's post to mean ...Is the sound of the ABS pump working being mistaken as a 'buzzer' sounding by Mark?

 

[Mark A]

There isn't the normal pulsing of the pedal with the buzzer, suggesting that it isn't the ABS activating.

 

[Mark A]

I've checked the pads & they seem fine. The problem seems to to have become even more erratic and is only happening in town when whirling into and around roundabouts.

Mark

 

[panason1c]

Reference my earlier post then...............

The pads 'worn sensor' only activates a warning light.........

The only reference to a buzzer sounding in my ML handbook relates to the EBV feature (Electronic brake force distribution).. the buzzer sounds when there is a fault within the system but also the ABS and BRAKE warning lights are activated as well...But you said that no lights appear so its a bit of a head scratcher!.

You will probably need to hook up to MB's Star machine to read off any logged codes.

 

[Mark A]

Buzzer on ML

I have been to the local dealer & there isn't a fault code logged. The problem is intermittent & mainly happens within 5 - 15mins after the engine has been started (usually when going up / down a hill). The buzzer comes on for approx 15 seconds at a time with no lights shown on the dash.

Is there a tank for the power steering fluid as I haven't located one yet.

I bought the "manual" off of flea bay & it is as much use as a chocolate fire guard.

Any other ideas chaps ??

Mark

 

[panason1c]

The power steering reservoir is located underneath the large plastic engine cover and is on the right hand side (as you look at the engine)....There is no warning system fitted to indicate if the fluid level is low.

The only mention of a buzzer in my ML drivers handbook refers to the EBV (as mentioned previously) ........but i'm sure a fault would have been logged if that was the culprit...

 

[jberks]

Is there a buzzer fitted anywhere in the car?
Most mercs these days have a 'beep' or 'bong' warning sound - no buzzers. Hence, I don't think it's trying to tell you anything.
Now, buzzers are either a buzzing noise rather than an actual buzzer, or I have come across buzzers attached to after market tow bar electrics to tell you the indicators are working.

 

[panason1c]

The ML handbook specifically mentions a warning 'buzzer' in association with the EBV system.

The next time it sounds, try to locate the 'buzzer'......................................................................


and remove or disconnect it!

 

[Mark A]

Buzzer on ML-270

The problem went away and has now come back. It chirps away for a period of time and then I get a continuous buzzer squeal for approx 15 secs. After that little lot it goes back to chirping again. I have now narrowed it down to coming from the passengers footwell - but no further. The most bizzare thing is that I parked the car and it continued chirping away for a few mins even with the engine off.

Help, my sanity is starting to go. Nothing came up on the Mercedes diagnostics system.

 

[panason1c]

The problem went away and has now come back. It chirps away for a period of time and then I get a continuous buzzer squeal for approx 15 secs. After that little lot it goes back to chirping again. I have now narrowed it down to coming from the passengers footwell - but no further. The most bizzare thing is that I parked the car and it continued chirping away for a few mins even with the engine off.

Help, my sanity is starting to go. Nothing came up on the Mercedes diagnostics system.

Got it!.........I can state with certainty that it is the underbonnet 'ebox' (the large black box on the passenger side that contains the ecu, relays, etc) cooling fan that is making the noise you describe and is a well known common fault.
I had to replace mine because of the intermittent 'squeeling' noise caused by the motor bearings running dry........the new replacement fan is modified with improved bearings.......The fan is designed to continue to run for approx ten minutes after switching off the engine to cool down the electronics which is the reason why you still hear it after switching off...........your initial posts threw me because you described the noise as a 'buzzer'.........

The cost of the fan is about £80 from MB though i bought mine directly from a Bosch agent for about £50............

It comes as a complete unit (as in pic)

http://rb-aa.bosch.com/aa/elektromotoren/en/elektromotoren/produkt/0130002828/index.htm