Brake Wear Indicator Flashing

[auditray2007]

Hi Guys,

I have a Brake wear indicator flashing on my 1999 LS 400. All the pads are 75% and more and sensors check out ok. Fluid ok and disconnecting the fluid sensor changes nothing,

I have read many posts but no info relating to this particular issue. Is there some way to reset this light. Tried the battery disconnect but to no avail.

[landar]

What tests/checks did you perform to conclude that the sensors are ok?

[auditray2007]

I did a Continuity test and there was continuity.

[landar]

From what I understand, the wear sensor is simply a wire that gets cut when the pads wear to a certain level. So, a cut would mean open circuit(hi-z). An uncut sensor should be very low resistance, zero ohms in theory. Now, perhaps you need to leave the battery disconnected for a longer period to reset the warning. There is a third possibility that perhaps the sensor connector is corroded/dirty and thus essentially opening the circuit to the computer. Check that carefully. You can 'spoof' the system (permanently or temporarily) by shorting out the sensor system with a piece of wire at the connector itself.

[auditray2007]

Checked all of that and tried another set of pads but same result. I bypassed the sensor with a wire loop at the loom side but same result.

"You can 'spoof' the system (permanently or temporarily) by shorting out the sensor system with a piece of wire at the connector itself." how is this done? or is that bypassing?

[landar]

Another set of pads would not help as it is all up to the sensors. If the connection is open, you get the warning. I would double check both sensors again and make certain that both are closed(short circuit). Yes, 'spoofing' in this case is the same as 'bypassing'. With bypassing you are basically just fooling the system into thinking the sensors are ok. Again, it could be the sensor socket connector that is bad.

If you do not care about the warning, you can cut off the sensor head and just strip back a section of the wiring and wrap them together(solder and shrink wrap them). If you want to keep the sensing ability (recommended), I would buy a new sensor for both front and rear.

[auditray2007]

By another set of pads I should have said with different sensors also. So two sets of sensors (which all check out ok anyway) and by passing the sensors does not put out the light. New sensors are not going to correct the fault! Yes I want to retain the warning.

Does that warning suggest any other problems within the car, something unrelated to brakes.

[steve2006]

IIRC it also indicates low brake fluid.

[99L400]

The "Brake Wear" light would come on and flash after ~10 miles into driving on my 1999 LS400 (154,500 on the meter). I had the front and rear pads replaced all together. The rear pads were quite worn but not totally out. We (me and the mechanics) purposely checked the rear sensor and didn't noticed any wear on the sensor.

The light came back on flashing about 10 miles on my way home. I was going to replace the sensor line when I get a chance later since it's not a show stopper. The light continued to come on very predictably in trips over 10 miles for another week. Then, I just thought about it and tried the connector at the brake fluid. The fluid is at the "MAX" line. The connector was loose even it was clicked in. I pushed it in and out several times. Now the light has not come back for two days with 25 miles one-way commute each day. I am not sure it will apply to other people but it is so far so good for me.