ABS light after going from 3.23's to 3.73's
Dec 20, 2005 | 01:41 PM
#1
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ABS light after going from 3.23's to 3.73's
My brother in law just had his gears swaped out for some 3.73 and after driving it a short distance, his ABS goes on. Is this common? Never seen this happened before. He lives an hour away and have not been able to flash his pcm for the 3.73 gears. Will flashing his pcm for the new gear ratio stop the the ABS light from coming on?
Dec 20, 2005 | 01:46 PM
#2
I just upgraded from 3.42's to 4.10's and my ABS and Parking Brake lights come on. I am pretty sure that once the PCM is flashed it will go away.. Hopefully my 02 pcm will be in today and it will take care of my problem..
Dec 20, 2005 | 02:17 PM
#6
WERD, the VSS tells the abs what to do, and the ABS light comes on anytime there is a malfunction with the ABS system. With the new gear ratio, the VSS is all confused, and the ABS system is disabled. Not sure where he is at, but if there is ice, snow, or rain tell him to be carefull till he gets the PCM re-flashed to correct it, cause right now he doesn't have ABS. 
Dec 20, 2005 | 03:09 PM
#7
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Originally Posted by white1
WERD, the VSS tells the abs what to do, and the ABS light comes on anytime there is a malfunction with the ABS system. With the new gear ratio, the VSS is all confused, and the ABS system is disabled. Not sure where he is at, but if there is ice, snow, or rain tell him to be carefull till he gets the PCM re-flashed to correct it, cause right now he doesn't have ABS.
I've had some bad experinces with a grand marquis that had no ABS!
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Dec 20, 2005 | 03:21 PM
#8
Thats right. When the light is lit up, it means the ABS system found a problem during the self check, and dis abled it self. When th ePCM is re-flashed, it should be fine ABS and all 
Dec 20, 2005 | 03:59 PM
#10
If your interested in why you get a ABS light, my understanding is that the ABS senses the front wheels independently at the wheels (via the ABS sensors)but the rear are sensed together using the VSS (vehicle speed sensor, same as the speedometer). It is picked up at the transmission or transfer case, in front of the rear diff. The computer assumes the factory gearing and calculates the rear wheel speed based on that. In effect, it thinks the front and rear wheels are turning at different speeds.
Make any sense? I'll try to give a better explanation if it doesn't.
Make any sense? I'll try to give a better explanation if it doesn't.