BlueHorse

2004 525i

I had dealer checked the brake pads a few days ago, both front and back have 4~5mm left. Front brake service alert showed 5000 miles left, and rear alert showed 1500 miles left.

Today I decided to reset both the front and back brake inspection service alert in the dashboard (and iDrive). After reset, rear brake service alert now shows "-15000", and tells me pads need to be replaced. Front service alert shows "0", and tells pads need to be replaced as well. I searched on internet, and believe the cause is worn (or partial worn) brake sensors.

I'd like to wait till the pads are 1~2mm left, but meanwhile want to get rid of the annoying red alert in Dashboard and iDrive. Read somewhere (can't find it now) the break sensor works by measuring the electric resistance between its wires (which I assume there are only two wires, and are connected to the surface rubbing against the rotor). New sensor is supposed to measure less than 5 Ohm, and partially worn sensor has less than 470 ohms, and worn will show a much larger resistance.

Now my question - how can I trick the sensor, or disable it? As to tricking it, I am thinking just cut the sensor out, and connect the two wires directly (that means the resistance will measure less than 5 ohm). Or if I should be concerned about a short circuit here, maybe buy a resistor of say 1 to 2 ohms and solder in between the two wires?

Any way to disable it?

4~5mm could last me any year or two. Hate to throw away the pads for the sake of this silly sensor thing.

Thanks!

BlueHorse

Oh, one more thing - I'd like to avoid buying and putting in new sensors at this point, because I assume the worn out pads means the new sensors shall be grounded immediately by the rotor and wear out prematurely. Let me know if this assumption does not make sense.
Thanks.

BLooD

Why did you reset it? that makes no sense at all.

tooltec

I really don't understand why anyone would want to negate a safety function such as brake pad monitor for the sake of saving money.Imagine buying a used car where this had been done by the previous owner and not rectified before sale.TOTALLY IRRESPONSIBLE!

BLooD

Yup, my thoughts as well. No help from me on this one.

BlueHorse

This is the first time I feel surprised by comments in any forums I have been too. Maybe I don't understand the issue here...

I have never had a car with brake sensor before owning this one, and they were all perfectly safe to drive. Why is a BMW, with 5~6mm pads but a worn sensor, dangerous to drive? I can visually see the outer pads with plenty of life, and I plan to have the tire shop inspect both inner and outer pads every time I rotate tires just like I have been doing.

Guys, it is not about savings a few $. I believe people enjoy DIY because it gives you control - to someone that means replacing a part way before it is due, to others like me it is to make full use of the material. That is of course within safety limits. Why I should let a sensor as inaccurate as what I have to waste the remaining life of the pads?

As to why I reset it in the first place - the sensor said 1,000 miles before inspecting rear pads, and the dealer did that 1,000 miles sooner and said the pads are good for while.

tooltec

With your previous cars,inspection during a service procedure would determine if your pads needed changing.They were safe to drive if the pad thickness was OK.The point I was making is that a safety related monitoring system should not be tricked or disabled.If the sensor and pad thickness do not correlate,then further investigation is necessary.You could reset the oil change warning and choose not to change the oil but that would not be a safety issue.

BlueHorse

Thanks for the info. I appreciate it.

benhuang_ady

try to reset few more times,i got same problem last time to reset the light at my shop.
i just replaced the rear brake pad yestoday,come out the pad not even used half,it just cost me less than $100 but i still think not worth it.but once the brake warnning come on, you have to replace a new sensor,you cant reset a used sensor

madmawler

I agree with benhuang. A brand new aftermarket brake sensor costs less than $10.00. Reputable brake shops recommend replacing the used brake sensor with a new one every time you replace the pads. With ABS brakes, it is not wise to trick or provide false information to the brain that is responsible for keeping your car's brakes from locking.