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I have 1999 F-150 4x4 4.6L. When I take off from a stop light, when the truck begins to move(accelerating at about 2000-2500rpm), the ABS Light comes on. The light goes away after I cut the truck off, it doesn't at every stoplight, just every few days. Anyone had a problem like this before?
most common problem i have seen is the rear axle speed sensor. its about $25 from ford and real easy to replace. you can test the sensor with an ohm meter...about 1.4K ohm i think, but it sound to me like you may want to have the codes pulled. if you have a C1229 or a C1230 then replace the sensor and keep on truckin.
Your truck's symptoms are not of a faulty rear dif sensor that is most commonly seen hereabouts.
You need to have the codes read.
If you have rear-only ABS, you can pull them yourself (instructions are around here somewhere).
If you have 4 wheel ABS, you will need an ABS-capable scanner. These are quite a bit more expensive than the typical OBD-II scanner, so you will likely need to go to either a dealer or a well-equipped independent shop.
The ABS conducts a self-test when the truck starts moving. Yours is failing that test.
if the abs module was unable to self test then the light would stay illuminated.. and no , the abs does not conduct the self test when the vehicle start to move, it performs this at start up, that is why the light turns off and comes back on later if a fault is detected.....like a missing rear axle speed sensor input.
if the abs module was unable to self test then the light would stay illuminated.. and no , the abs does not conduct the self test when the vehicle start to move, it performs this at start up, that is why the light turns off and comes back on later if a fault is detected.....like a missing rear axle speed sensor input.
The ABS runs a startup self-test (to detect gross failures of sensors and actuators.) and runs continuous self-tests during vehicle operation to verify system performance.
From the service documentation:
The ABS control module is self-monitoring. When the ignition switch is turned to the RUN position, the ABS control module will do a preliminary electrical check, and at approximately 20 km/h (12 mph), the pump motor is turned on for approximately one-half second. Any malfunction of the ABS system will cause the ABS to shut off; however, normal power assisted braking remains.
Without the actual code(s), everyone is only guessing.
Steve
Last edited by projectSHO89; Dec 13, 2005 at 10:35 AM.
i was only making a guess based on years of experience...i could be right or wrong. codes would definitely take the guessing out, but it sure would be nice if it was a simple and cheap repair.