Does My Abs Work?

nfs13b · February 28, 2011

Hello All,

I have a question about the ABS on my 2003 2500HD....

When the 'reds' are on the ABS light is on then goes out, which to me means things are ok... When the car is on there is a noise that seems to come from the unit every now and then (the unit is under the car on the left side correct??)

When I press the brakes hard though they lock up which obviously means I have a problem....

What can I do to check this? I dont get any fault codes on the EFI Live program....

HELP...

8.1HD/ALLISON · March 1, 2011

Take it somewhere and have codes checked.

nfs13b · March 1, 2011

Take it somewhere and have codes checked.

Oh forgot to mention I am in Australia and its hard to find anyone here that can help.....

Nytemare · March 1, 2011

Hello All,

I have a question about the ABS on my 2003 2500HD....

When the 'reds' are on the ABS light is on then goes out, which to me means things are ok... When the car is on there is a noise that seems to come from the unit every now and then (the unit is under the car on the left side correct??)

When I press the brakes hard though they lock up which obviously means I have a problem....

What can I do to check this? I dont get any fault codes on the EFI Live program....

HELP...

If there is no light on during driving or sitting idle your likely working fine. The wheels will lock up if you hammer the brakes. That's how they work...you don't just coast to a stop cause you have ABS...however while your tires are screaming you should hear a god awful grinding noise while your on the brakes hard....and the peddle should pulsate. This is the brake applying and letting go.

If your not going fast enough when you hammer your brakes you wont even get this, you'll just stop.

Oh and a Holden shop should have a Tech II scan tool. They need it for the LS series engines.

8.1HD/ALLISON · March 1, 2011

I'm kinda confused on the lights you described. When you first start the truck all the lights should come on for a few seconds, then go out(bulb check). If that is happening the abs is operating normally. Take the truck down the road at 30 or 40 mph and try to lock the brakes up. As mentioned above they pedal should pulsate and buzzing noise should be heard.

nfs13b · March 1, 2011

Nytemare,

I dont hear a grinding sound and if the pedal pulsates its very faint, not like other cars I have driven with ABS (all smaller than a silverado)

And the local holden dealers want nothing to do with it, over here dealers stay far far away from most imports and give no assistance...

I'm kinda confused on the lights you described. When you first start the truck all the lights should come on for a few seconds, then go out(bulb check). If that is happening the abs is operating normally. Take the truck down the road at 30 or 40 mph and try to lock the brakes up. As mentioned above they pedal should pulsate and buzzing noise should be heard.

Yes the lights im saying is when you turn the key to the on position and or start the truck and the bulbs all check themselves...

It happens at low speeds to, if I am driving at like 40km/hr which is like 25mph and hit the brakes the wheels will lock and will slide.... is that normal?

See when I bought the truck locally (I didnt import it unfortunately) the ad said it had "aftermarket ABS" which I thought was very strange but I thought the people just didnt know what they were on about... Also when the truck is converted from left to right hand drive the master cylinder is moved etc so I am wondering if perhaps all this time the ABS has not been bled properly or maybe its all just in my head...

I know when I tow my 28ft car trailer (4000kg) I need to have the electric trailer brakes on max because if I dont I wont pull up very quickly....

nfs13b · March 1, 2011

oh and I do hear random buzzing/ tut tut tut tut noises from the passenger (USA drivers) side at random times when idling (cant hear when driving over exhaust/engine noise)

Finally, If I am idling and I push the brake pedal I get like an air sucking/escaping noise coming from under the dash, when I looked its like the back of the master cylinder is pressurised and when you push the pedal in it cracks the seal and the air escapes (where the rod pushed into the master cylinder)

Is that normal?

Nytemare · March 1, 2011

oh and I do hear random buzzing/ tut tut tut tut noises from the passenger (USA drivers) side at random times when idling (cant hear when driving over exhaust/engine noise)

Finally, If I am idling and I push the brake pedal I get like an air sucking/escaping noise coming from under the dash, when I looked its like the back of the master cylinder is pressurised and when you push the pedal in it cracks the seal and the air escapes (where the rod pushed into the master cylinder)

Is that normal?

That's normal sounds...and there's no air in there...its a vacuum can.

If the light isn't on your ABS is working properly. And if its not, count your lucky stars...I would love to have no ABS. I don't need a damn computer to pump my brakes.

Unless the fuse is gone for the ABS computer. Than everything acts normally, but the ABS is non existent.

So check your fuses, Your brakes are fine from the sound of things. And remember that you will only hear the grinding sound and heavy pulsation if you really tromp on the brake for a panic stop or if your on gravel and tap the brakes and something locks. Also, if your wheels do lock, don't pump the peddle, that negates the effects of the ABS system.

I also have never heard of an aftermarket company making an ABS for passenger vehicles. Would be very sketchy at best. Maybe an aftermarket ABS Delete.