S8 D3 Brake Pad Wear Indicator Always On
Thread Starter
AudiWorld Junior Member
Joined: Apr 2024
Posts: 6
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From: Ferndale, WA, USA
S8 D3 Brake Pad Wear Indicator Always On
Hello all, long time viewer and first time poster.
I am having an issue with my 2007 S8 D3 involving the brake pad wear indicator on the instrument cluster. The cluster continually shows the yellow brake pad malfunction. I am a professional technician and own/operate an automotive repair shop (as well as a licensed electrician), however I have exhausted my resources trying to diagnose this issue.
Using Alldata, I found the wiring diagram for the brake pad wear sensor circuit. It appears the circuit starts at pin 7 on the back of the instrument cluster (T32). The red wire at pin 7 on T32 then travels to the connector for the front left brake pad wear sensor and terminates at pin 1. Pin 2 of the pad wear sensor (yellow wire) then travels to pin 2 of the front right pad wear sensor connector. Pin 1 of the right wear sensor connector (red wire) travels into the cabin and is grounded to the chassis at location G43 behind the outer kick panel on the right hand side of the vehicle. Of course the wear sensors are simple 2 wire sensors, so they simply loop pin 1 and 2 on the left and right wear sensor connectors in order to complete the circuit. From my understanding this circuit is all about continuity and a malfunction will appear when the circuit is broken.
I purchased the vehicle with this condition (for a good deal), thinking I would know how to remedy this issue no problem. Original brake pads still had plenty of friction material and sensors appeared in good shape, however I replaced all front brake pads along with the wear sensors so they are new. I have tested continuity between pin 7 at T32 and pin 1 at the left wear sensor connector, pin 2 at the left wear sensor connector to pin 2 at the right wear sensor connector, and pin 1 at right wear sensor connector to G43 in cabin, all with good continuity, I have tested continuity on both of the wear sensors themselves, unplugged, both good, All connector pins are straight, no corrosion. Cleaned both connectors and applied dielectric grease. I have also bypassed both sensors with a solid piece of wire to no avail. The malfunction is constant, it has been present since the day it was purchased.
Has anyone here personally experienced this issue? I have contemplated taking the red wire at pin 7 of the instrument cluster and grounding it directly to the chassis to determine if the instrument cluster is failing internally, however I would prefer to avoid splicing into a factory loom if possible.
Thanks in advance!
I am having an issue with my 2007 S8 D3 involving the brake pad wear indicator on the instrument cluster. The cluster continually shows the yellow brake pad malfunction. I am a professional technician and own/operate an automotive repair shop (as well as a licensed electrician), however I have exhausted my resources trying to diagnose this issue.
Using Alldata, I found the wiring diagram for the brake pad wear sensor circuit. It appears the circuit starts at pin 7 on the back of the instrument cluster (T32). The red wire at pin 7 on T32 then travels to the connector for the front left brake pad wear sensor and terminates at pin 1. Pin 2 of the pad wear sensor (yellow wire) then travels to pin 2 of the front right pad wear sensor connector. Pin 1 of the right wear sensor connector (red wire) travels into the cabin and is grounded to the chassis at location G43 behind the outer kick panel on the right hand side of the vehicle. Of course the wear sensors are simple 2 wire sensors, so they simply loop pin 1 and 2 on the left and right wear sensor connectors in order to complete the circuit. From my understanding this circuit is all about continuity and a malfunction will appear when the circuit is broken.
I purchased the vehicle with this condition (for a good deal), thinking I would know how to remedy this issue no problem. Original brake pads still had plenty of friction material and sensors appeared in good shape, however I replaced all front brake pads along with the wear sensors so they are new. I have tested continuity between pin 7 at T32 and pin 1 at the left wear sensor connector, pin 2 at the left wear sensor connector to pin 2 at the right wear sensor connector, and pin 1 at right wear sensor connector to G43 in cabin, all with good continuity, I have tested continuity on both of the wear sensors themselves, unplugged, both good, All connector pins are straight, no corrosion. Cleaned both connectors and applied dielectric grease. I have also bypassed both sensors with a solid piece of wire to no avail. The malfunction is constant, it has been present since the day it was purchased.
Has anyone here personally experienced this issue? I have contemplated taking the red wire at pin 7 of the instrument cluster and grounding it directly to the chassis to determine if the instrument cluster is failing internally, however I would prefer to avoid splicing into a factory loom if possible.
Thanks in advance!
AudiWorld Wiseguy
Joined: Aug 2012
Posts: 4,071
Likes: 321
From: Chicago
Are you sure it’s not the rear brake pad wear indicator? That doesn’t use physical wear sensors, rather it derives pad thickness by counting the number of revolutions of the parking brake motors. The warning on the dash is the same weather it’s the front or rear pads.
Thread Starter
AudiWorld Junior Member
Joined: Apr 2024
Posts: 6
Likes: 0
From: Ferndale, WA, USA
I replaced rear pads as well and performed the brake pad replacement procedure. Also reset the pad depth after replacement. When looking at parking brake measuring blocks, it shows the depth at 10mm where I set it after replacement.
AudiWorld Wiseguy
Joined: Aug 2012
Posts: 4,071
Likes: 321
From: Chicago
Ok. I think you need to short the appropriate pins/wires that are directly connected to the cluster, see if the fault goes away. If it doesn’t, the cluster is bad. Might be something that a modulemaster or similar could perhaps fix.
Thread Starter
AudiWorld Junior Member
Joined: Apr 2024
Posts: 6
Likes: 0
From: Ferndale, WA, USA
I will update as soon as I have free time to dig back in.
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