ABS problem diagnosis?
 

My car has had the ABS light on for months now but until 2 days ago it never affected the driving at all. But just recently the light went off and the pedal will firm up unexpectedly and the brakes become useless. if i pump the brake it eventually goes back to normal. And at times it doesnt feel smooth, when i depress the brake it feels like it has hard lumps im pushing through.

And just yesterday i started my car to test it out and the light was on again and the brakes acted as they should normally.

This really worries me and if anyone can fill me in on what this could be that would be appreciated before i get raped at a repair shop:)

Re: ABS problem diagnosis?
 

Have you checked your ABS codes on the car?

I copied a post from SVXCESS:

B: SELF-DIAGNOSIS

Conduct self diagnosis after driving the vehicle at speeds greater than 19mph for at least one minute. The vehicle must be stopped with the engine operating. When a problem is detected by self-diagnosis, the warning light on the instrument panel comes on.

Approximately 5-12 seconds after the warning light has come on, the problem detected by the ABS control unit (located under the right front seat) is displayed by a trouble code in terms of "the number of LED blinks"

Both the warning light and the LED remain activated unless the ignition is turned OFF. With the ignition key turned OFF, the contents of the problem stored in the memory are reset.

Only one trouble code is displayed at a time. When a multiple of problems occur, only the first problem detected is displayed.

If the LED does not activate (though the warning light is ON) the power supply may be inoperative.



C: LIST OF TROUBLE CODES

00 (LED OFF)...Improper power line voltage or faulty harness.
01...Broken or shorted solenoid valve circuit(s) in hydraulic unit ..LEFT FRONT WHEEL CONTROL
02...Broken or shorted solenoid valve circuit(s) in hydraulic unit ..RIGHT FRONT WHEEL CONTROL
03...Broken or shorted solenoid valve circuit(s) in hydraulic unit ..RIGHT REAR WHEEL CONTROL
04...Broken or shorted solenoid valve circuit(s) in hydraulic unit ..LEFT REAR WHEEL CONTROL

05...Faulty wheel ABS sensor ..LEFT FRONT WHEEL SPEED
06...Faulty wheel ABS sensor ..RIGHT FRONT WHEEL SPEED
07...Faulty wheel ABS sensor ..RIGHT REAR WHEEL SPEED
08...Faulty wheel ABS sensor ..LEFT REAR WHEEL SPEED

09...Faulty motor and/ or motor relay or broken or shorted harness circuit.
10...Faulty valve relay or broken or shorted harness, or interrupted ABS (causing brakes to function as a conventional brake system.) Unidentified fault that are not equivalent to trouble codes 1-16

16...Faulty ABS Control Unit or broken or shorted harness or malfunctioning system or line unidentified by vehicle ABS sensor fail-safe function.

Re: ABS problem diagnosis?
 

I too am having and issue with my ABS light staying on all the time, and as of yet it hasn't caused any noticeable issues. However I can't seem to find the actual LED that throws the codes, I've looked under both driver and passenger front seats, and have yet to see any flaps of carpet or LED. Am I just not looking in the right places, and I have moved the seats forward and back all the way.