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Hey, if this is the wrong place for this, I apologize. Please move if needed
I have a 1999 f150 4x4 4.6 and it’s has an ABS light on. I read that it might be the sensor in the axle pumpkin and I changed that but it didn’t do anything. If I turn the ignition and step on the brake before all the lights go off, the light will not come on. If I turn the ignition on and do not press on the brake, the light comes on. I’m not sure how to fix it.
Which ABS system do you have?
Four wheel or two wheel?
The systems are different.
Read closely.
At key on, the ABS module is self tested.
The sensors cannot be tested at this time because the truck is not moving hence no signal generated to send to the module.
A resistance test could be good but no signal generated unto movement over about 5 mph.
When that sets the ABS there is a code associated with it that must be read with a Scanner on 4W ABS system.
Guessing is not the way.
Good luck.
I’m not sure if it’s 2 or 4 wheel, but I now that it comes on before I am even moving, but if I press the brake before I start it, the light doesn’t come on.
when you start the truck ( key on) the light comes on for 3 seconds and basically a continuity test is run to see if everything is plugged in... If OK, the light goes out....... after you start moving, a speed check is done about 5 MPH and if the sensors don't agree, then the light comes back on.. that means the sensor is connected, but is not working ( reading teeth)... Normally if you have multiple sensors, there is one on each front wheel and one in the rear pumpkin.
Does the light go out after 3-5 seconds, before you start to move ? If not, then "normally" one of the wires or sensors is broken or unplugged ........ it failed the continuity test to check wires / sensor.... if you changed the rear sensor, then look at the wires behind the wheel hubs on the front.. damaged ? ...trace them up a foot or so and see if the electrical plug is still connected
No it never goes out. The front two sensors are fine. I did some searching and had the code checked and apparently it’s due to a failed ABS motor/pump circuit. Apparently most of the times it’s the control module and I don’t want to pay $400 for the light to go out. Would a bad pump cause the normal breaks to be soft? Opinions?