Dashboard Brake Light and PST2

My brake sensors comes on randomly, usually when I press breaks. It started happening after I put on new wheels and they grinded the rotors to get rid of rust. Not sure if the two are related. Sometimes I can drive few kms without the light coming up on the dashboard. Is there anyway with PST2 to tell which sensor is giving up the error code? What is the repair procedure otherwise? Replace all sensors? I guess I should check the breaks as there must be a reason why the sensor comes up. Thanks for any help

Check your brake pads all round. The brake sensor touches onto rotar when the pad gets worn enough to allow the sensor inside it to touch the rotar. If you are a DIY man its an easy job to do brakes on the 996 with help from you tube. The dash warning light will not indicate which pad is causing the light to come on so change the pads all around or at least on the same axle as the one to the one which is causing the light to come on. If you need further help message me as i have done my brakes and I dont class myself to be a first class DIY man. You will meet one snag removing the old pad which I can help you with. Dont be tempted to remove the sensors or leave out the anti squeelers when changing the pads. Some will say get rid of them but they are usually track men who change their brakes more than I change my shirt lol..

Low brake fluid?

There are two brake lights on your instrument cluster. Which one is it? The one that says "Brake" is low brake fluid warning. The one that says "Brake Wear" are your pad sensors. Brake pad sensors are just wires. when the wire gets worn through the sensor light will on (and usually stay on) as the wire is broken connection at that point.

You cannot use the PST2 or like device to determine which sensor is sending the signal. The brake wear function is a simple circuit that runs daisy chain to each wheel. When a sensor wears through the circuit is broken and the light goes on. If none of the sensors appears worn through the internal wires you check them for continuity with a voltage meter. My brake wear light was on for 2+ years and I could not find the source. I checked and replaced the sensor, pads again and again and could not find the problem. Finally one day when I was adjusting my rear PSS10's I saw a burn mark on the label of the main wiring harness under the storage compartment for my cab top. Then began the search. I unwound the tape on the harness at the label and found a melted brown/ground wire, .5 size, that was also melting the insulation on surrounding wires. Started tracing it and about 18" away it went into a cluster of larger gauge ground wires at ground point 8. Where it joined this cluster the insulation was not melted. Then I began tracing it the other direction. A major pain, out came the rear seats, the rollbar frame and assembly, the rear carpet as I slowly unwound the harness and traced the wire to an area behind the drivers seat, melted all the way, where it turned back on itself. Finally traced it back to wear it met the two brake sensor harness' for the rear wheel, which were a much heavier gauge wire. At this point the insulation was again intact. I never figured out what cuased the insulation on this wire to melt, it must have had a surge or short of some sort, but I now knew why my brake wear light was on. I had a tangle of unwrapped wiring harness, literally hundreds of wires. I ended up running a new ground wire, heavier gauge similar to the ones the melted wire connected. Then put everything back together. No problems since. I hope your problem is not such a PITA.

Yeh if your brake sensor light is on you can bet its worn pads. The pad wears enough and allows the sensor wire which is inside the pad to touch the rotar therefore breaking the daisy chain by grounding it out onto the rotar itself.

I believe that the way the brake pad sensors work is that as they hit the rotors you wear through the plastic material and ultimately through the wire imbedded in the plastic. When the imbedded wire wears through the circuit is broken and the light comes on. I don't think it has anything to do with grounding on the rotor.

Looks like my front pads are hitting the sensor. Should I replace all sensors when I change my pads or just the front sensors? or no sesnsor?

Change the front pads and put new sensors in the new ones. You will need to remove the calipers to get the pads out.

You don't have to remove the calipers to change the pads!

Quotes source post: 9703874

Do i need the "Brake Pad Retainer Kit" from pelican parts or my old one should be fine?

When I changed my front pads and rotors I was able to reuse the old sensors, but bought new ones anyway, just in case.They are pretty inexpensive to have as spares.

Quotes source post: 9705896

Do you buy the brake retainer kit or used the old parts? not sure if I should but the kit, pelican parts says that I should buy it with the brake pads.

You can go either way. I swap my pads our pretty frequently (street to track and back) so I don't replace the retainer kits every time. However, if you're not tracking and this is going to be the only time you replace the pads until new ones are required, I'd get the retainer kit. Nice new parts make the reassembly (and future dissassembly) much easier.