After the previous owner replaced the pads and rotors, there was still a "Check brake pads" message and the amber "Brake" lamp was on.
I don't really need the car to tell me when the brake pads are low, so I followed the steps in Body's Brake Bible to bypass the sensors. I cut the wires right by the calipers, stripped them back a bit, twisted them together, wrapped them in electrical tape and secured them with a zip tie.
According to Bodsy, "It will think that the circuit is completed and therefore that the brakes are OK." - BUT, the dash message and lamp are still there even after clearing all the codes and disconnecting the battery for a while.
Is there something else that needs to be done to re-set the system? I noticed some tape on the rear sensor connector, which tells me that the previous owner probably broke it, so maybe that circuit is still open?
20th Aug 2024 11:43 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10628
It’s the wires on the car side you need to join together. (Not caliper).
Alternatively try connecting both front wires together and then to a ground point.
21st Aug 2024 6:41 am
rythomas
Member Since: 10 Aug 2024
Location: BC
Posts: 6
Quote:
It’s the wires on the car side you need to join together. (Not caliper).
Aren't they the same wires from the sensor all the way to the connection / harness? At the caliper they're are just held in place by the bleeder cover, should be no difference joining them on either side of that, no?
How does the sensor work in principle? It's a closed circuit that is somehow interrupted when the pads get too low and the sensor gets squeezed or worn?
I'll try grounding them but I'm curious how / why that would work.
21st Aug 2024 7:20 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10628
From memory one connection at the rear is ground.
The other connection goes to front sensor.
So the sensors are in series.
The other front wire connects to dash for monitoring.
Yes, if circuit broken by worn pad is triggers alarm.
So connecting front wires to ground should silence it
21st Aug 2024 9:00 am
loanrangie
Member Since: 18 Jun 2017
Location: Melbourne
Posts: 679
Wires need to be joined on the vehicle side not the caliper side.
21st Aug 2024 11:51 am
rythomas
Member Since: 10 Aug 2024
Location: BC
Posts: 6
Quote:
Wires need to be joined on the vehicle side not the caliper side.
This is the part that's confusing me, what's the difference between vehicle side and caliper side? Vehicle side of what?
21st Aug 2024 6:17 pm
rythomas
Member Since: 10 Aug 2024
Location: BC
Posts: 6
Pete K wrote:
From memory one connection at the rear is ground.
The other connection goes to front sensor.
So the sensors are in series.
The other front wire connects to dash for monitoring.
Yes, if circuit broken by worn pad is triggers alarm.
So connecting front wires to ground should silence it
Sounds about right, the service manual says the same thing:
Quote:
The front brake pad wear sensor is connected in series with the rear brake pad wear sensor, between the instrument
cluster and ground. When a brake pad incorporating a brake pad wear sensor is approximately 75% worn, the brake pad
wear sensor goes open circuit. When the instrument cluster detects the open circuit, it illuminates the amber Light
Emitting Diode (LED) in the brake warning indicator. Vehicles with the high line instrument cluster also display an
appropriate warning in the message center and sound a warning chime.
21st Aug 2024 6:45 pm
loanrangie
Member Since: 18 Jun 2017
Location: Melbourne
Posts: 679
rythomas wrote:
Quote:
Wires need to be joined on the vehicle side not the caliper side.
This is the part that's confusing me, what's the difference between vehicle side and caliper side? Vehicle side of what?
If you cut the wires just out from the caliper and joined the section closest to the caliper it does nothing, you need to join the other section that goes up under the guard liner.
Also have you checked the rear sensor as either will turn the light on.
22nd Aug 2024 12:39 am
rythomas
Member Since: 10 Aug 2024
Location: BC
Posts: 6
Oh I think I get what you mean... I removed the sensors entirely, so the wires that I joined are the ones on the car side that would complete the circuit from ground to the instrument cluster.
I did the rear sensor wires as well, haven't tried grounding the front ones yet but I expect that will do the job. I'm guessing that the core of the issue is that the starting point (C2922-1 on the diagram) isn't grounded properly or the rear sensor connector is bad. I'll investigate with the circuit tester when I have some time this weekend, there are a couple other issues that could be explained by bad grounds at the rear of the car as well so it's worth it to diagnose this a bit before skipping to the finish line.
Click image to enlarge
22nd Aug 2024 5:38 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10628
Often wire running down the suspension arm, (where it flexis with road conditions and height) can break over time rather than the sensor itself.
So it's better to join the wires as close to the car connector as possible, rather than on the end.
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