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Brake pad sensor fuse

 
  #1  
Old 03-04-2019, 12:54 PM
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Default Brake pad sensor fuse

The low pad warning came on in my car. I checked the pads and they are all good. I know that the warning could come on if there is a broken wire, but it is too darn cold to work on the car outside. I am tired of the warning light, is there a fuse for that circuit? If so, which one, and what else is on the circuit.

Thanks,

Maynard
2011 XF 5.0
 
  #2  
Old 03-04-2019, 02:22 PM
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Sadly, warnings like that don't really sit behind fuses as such, so you can't just stop the warning by yanking a fuse. The brake pad wear sensor is not integral to the pads on these cars, it is separate and needs to be replaced with them as it wears down (though people often won't). It might be possible to replace it with a resistor of a known value (though I can't help with which value off-hand) but I know if you just disconnect the wear sensor the warning will still show as it will be detected as open-circuit.
 
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Old 03-04-2019, 03:16 PM
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No resistor needed to "false" the system into a normal state, you need to unplug the sensor wire from the chassis harness. Then on the sensor wiring (only 2 wires), cut them leaving about 3 inches from the plug that plugs into the chassis harness and strip back the insulation and twist together, then tape it up and plug it back into the chassis plug.

That will "fool" the check system and remove your warning.

When you buy a new sensor and replace your pads, you just unplug and throw away the spliced old sensor wiring and plug in the new one.

Is just a basic open/closed circuit. If the circuit is open, it is in alarm, if it is closed, normal.

I will try and find the picture i took when i did that a few years ago until I could get new sensors fitted with the new pads.
 
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Old 03-04-2019, 04:58 PM
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oh look I was wrong again lol
 

Last edited by Brutal; 03-05-2019 at 09:03 AM.
  #5  
Old 03-04-2019, 07:45 PM
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Originally Posted by Brutal
No the sensor is a ground circuit. When the pads are worn into the sensor it contact the rotors completing a ground circuit and turning on the light. If the pads are not worn to the sensor then look to see if one of the wires is contacting the wheel inside(most common)
Are you sure about that brutal? It looks like two wires that are connected with a metal loop in the sensor head that you place in the pad. When the head of the sensor wears down and wears through the metal loop it creates an open circuit and gives a warning

If it was contact with the rotor it would flash on and off each time you use the brake

Similarly if you just unplug the sensor wire it will show the low pad warning
 
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Old 03-04-2019, 10:15 PM
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Originally Posted by BritCars View Post
Are you sure about that brutal? It looks like two wires that are connected with a metal loop in the sensor head that you place in the pad. When the head of the sensor wears down and wears through the metal loop it creates an open circuit and gives a warning

If it was contact with the rotor it would flash on and off each time you use the brake

Similarly if you just unplug the sensor wire it will show the low pad warning

Yep. All you need to do is short out the old wires until you get a new sensor and install it on new pads.

I have done it as I replaced my pad before either the front or rear tripped so I did not buy new ones and when I attempted to remove the old ones from the old pads, they broke. So it took a week to get the new sensors in but I needed my car so I cut the old sensor cables up and reconnected for a week.

Super simple, I even contemplated leaving them that way until I found the you could get aftermarket ones for $20 a set (Ford uses the same sensors).
 
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Old 03-05-2019, 09:00 AM
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actually no I was assuming that since I have had cars come in with aftermarket brakes and no sensors hooked up that it wasn't looking for the open circuit. According to the workshop manual that is what it looks for. Now why the light is not triggered when there are no sensors...……..??????
 
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Old 03-05-2019, 04:53 PM
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Originally Posted by Brutal View Post
actually no I was assuming that since I have had cars come in with aftermarket brakes and no sensors hooked up that it wasn't looking for the open circuit. According to the workshop manual that is what it looks for. Now why the light is not triggered when there are no sensors.....??????
As mentioned before if you simply remove one or both sensors completely you will get the "low brake pads" warning light, as the system is looking for a closed circuit and if you have no circuit that is interpreted by the system as an open circuit = worn through sensor.
Two ways to avoid that without connecting up new sensor(s) - leave the electrical plug connected but cut and join the two wires or get the system disabled via the CCF using SDD. I had the system disabled on both my XFR and F-Type by Cambo.
 
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Old 03-05-2019, 05:31 PM
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Originally Posted by OzXFR View Post
As mentioned before if you simply remove one or both sensors completely you will get the "low brake pads" warning light, as the system is looking for a closed circuit and if you have no circuit that is interpreted by the system as an open circuit = worn through sensor.
Two ways to avoid that without connecting up new sensor(s) - leave the electrical plug connected but cut and join the two wires or get the system disabled via the CCF using SDD. I had the system disabled on both my XFR and F-Type by Cambo.
Ox I understand what you said earlier. I was referring to why I have had several cars with indie shops that did brakes and did not install sensors and there was no light. And I don't mean indie like Jaguar indie, but like Firestone and Brake check specifically. I will have to try next time I do a set of pads and leave the sensor unplugged from the car and see if that works or not.
 
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Old 03-05-2019, 05:56 PM
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Originally Posted by Brutal View Post
Ox I understand what you said earlier. I was referring to why I have had several cars with indie shops that did brakes and did not install sensors and there was no light. And I don't mean indie like Jaguar indie, but like Firestone and Brake check specifically. I will have to try next time I do a set of pads and leave the sensor unplugged from the car and see if that works or not.
All I can think of is that those indie shops cut and joined the sensor wires.
Up by the plugs so you can't see them without taking the wheels off and looking right up in the wheel wells.
 
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Old 03-06-2019, 09:59 AM
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Originally Posted by ozxfr View Post
all i can think of is that those indie shops cut and joined the sensor wires.
Up by the plugs so you can't see them without taking the wheels off and looking right up in the wheel wells.
nope, there was no connector on the body harness side. 1 customer was pissed because he showed me the receipt and he paid for 2 sensors
 
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Old 03-06-2019, 10:53 AM
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That is strange. I know from mine if you take off the sensor altogether you get an error.
 
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Old 03-06-2019, 03:53 PM
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OK I just verified that yes even unplugged it turns on the warning on the XJ I just did. My thoughts on why the light was not on for the cars that some other shop did brakes on and left the sensors off was that they must have put a small wire in either the front or back of the connectors and I just didn't see them. learned something new that I really didn't have a need to know before.
 
 
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