ABS Warning Light
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Postmaster
Joined: Aug 2001
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From: Delaware
ABS Warning Light
I just replace the front rotors and pads on my 2002 Mountaineer. Now after I drive a little, the ABS warning light illuminates. The manual says that this means that the ABS system is disabled.
Are my new brakes hanging and causing a problem?
Is this something that will stop as the new pads seat?
Are my new brakes hanging and causing a problem?
Is this something that will stop as the new pads seat?
Senior User
Joined: Sep 2003
Posts: 254
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From: Colorado
Might need to bleed the system. I don't know how things work on that new of a vehicle, but my ABS light comes on when there is a problem with pressure in the brake lines (meaning air in the lines).
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Postmaster
Joined: Aug 2001
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From: Delaware
I didn't open the system or lose any fluid. The master cylinder is full. The brakes stop fine, don't pull or fade or feel spongy. I think that the ABS light goes on after I make a turn. I am not sure if it is a right or left turn or both.
Mountain Pass
Joined: Dec 2001
Posts: 213
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From: Kernersville, NC
I would look under the truck and make sure all the connections to the wheel speed sensors are still clean and connected firmly. I've disconnected these once or twice on cars to keep the wiring out of the way on a brake job only to forget to reconnect them. Autozone will pull the codes for free usually, that will help you find a place to start looking.
I have heard many techs suggest that pushing the old brake fluid back into the system is a bad idea. I always open the bleeder when I push the piston back in before putting on new pads. Then again, I usually flush my brake fluid once every two years or so. Cheap insurance for me who keeps cars for a long time.
Bryan
I have heard many techs suggest that pushing the old brake fluid back into the system is a bad idea. I always open the bleeder when I push the piston back in before putting on new pads. Then again, I usually flush my brake fluid once every two years or so. Cheap insurance for me who keeps cars for a long time.
Bryan
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Postmaster
Joined: Aug 2001
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From: Delaware
OK, I'll look at the connections and If I find nothing there, I'll get the codes read at Autozone or somewhere.
I have always pushed the brake fluid back into the master cylinder when replacing pads. The fluid in the caliper is the same as the fluid in the reservoir. It is moisture that contaminates brake fluid, and the less the system is opened, the less moisture gets into it.
I have always pushed the brake fluid back into the master cylinder when replacing pads. The fluid in the caliper is the same as the fluid in the reservoir. It is moisture that contaminates brake fluid, and the less the system is opened, the less moisture gets into it.
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Postmaster
Joined: Aug 2001
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From: Delaware
OK, I looked at the connections as much as possible without pulling the wheels and rotors off. It looks OK, but I can't tell for sure.
How do the wheel sensors work? I didn't look at them when I had the rotor off.
BTW, the ABS light always goes out after a restart. The problem must occur during driving and applying the brakes. It seems like it is due to some uneveness in the braking, like one set of pads dragging. It also seems to occur during a turn.
How do the wheel sensors work? I didn't look at them when I had the rotor off.
BTW, the ABS light always goes out after a restart. The problem must occur during driving and applying the brakes. It seems like it is due to some uneveness in the braking, like one set of pads dragging. It also seems to occur during a turn.
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Mountain Pass
Joined: Dec 2001
Posts: 213
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From: Kernersville, NC
The codes will give you the best indication where the problem is, since everything looks okay upon initial inspection. The ABS system runs a self test when you first start off, from 0-10mph. It cycles the ABS pump and such. When driving, it is looking for unusual readings from the speed sensors mainly.
The speed sensors on most cars are Hall effect sensors which rely on a toothed rotor passing near a magnetic pickup to generate a current which is used by the PCM to detect wheels speed and acceleration. When the sensors from two wheels suddently don't match, then the PCM knows that one wheel is sliding and or spinning(for the traction control which often uses the same sensors to determine wheelspin). On my cars, there is a toothed ring right on the driveshaft going to each wheel.On my truck, with a solid rear axle, it's located in the differential.
One other thought. The 4WD on my truck diables the ABS, but mine's a 94' so they may have resolved things later on? Have you had the truck in 4WD since then?
Bryan
The speed sensors on most cars are Hall effect sensors which rely on a toothed rotor passing near a magnetic pickup to generate a current which is used by the PCM to detect wheels speed and acceleration. When the sensors from two wheels suddently don't match, then the PCM knows that one wheel is sliding and or spinning(for the traction control which often uses the same sensors to determine wheelspin). On my cars, there is a toothed ring right on the driveshaft going to each wheel.On my truck, with a solid rear axle, it's located in the differential.
One other thought. The 4WD on my truck diables the ABS, but mine's a 94' so they may have resolved things later on? Have you had the truck in 4WD since then?
Bryan
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Mountain Pass
Joined: Dec 2001
Posts: 213
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From: Kernersville, NC
Re brake fluid, the brake fluid needs to be flushed regularly on any vehicle. Most master cylinder caps have a vent on them anyway so moisture always gets in the master cylinder reservoir that way. Opening the bleeder won't make things any worse. The fluid in the calipers also can break down due to heat. When I am prepping my cars for a driving shool or autocross season, I always flush the fluid. It's actually required by the sanctioning body and/or insurance co. covering the event and a regular part of tech inspection.
Bryan
Bryan
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Postmaster
Joined: Aug 2001
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From: Delaware
I hooked up my desktop computer and used OBDII software to read the codes. I had to use a desktop, because my laptop doesn't have a serial port to connect the OBDii interface cable.
I did not have any error codes. I even drove the Mountaineer until the ABS warning light came on, and left it run while I checked the codes. Still no error codes appeared.
Can anyone tell me which mode would contain ABS data?
I did not have any error codes. I even drove the Mountaineer until the ABS warning light came on, and left it run while I checked the codes. Still no error codes appeared.
Can anyone tell me which mode would contain ABS data?