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aka: bigford84
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Discussion Starter #1
somtimes after having to press on the brake kinda hard, the rabs light will come on and it will be harder to stop. plus the rear brakes will drag hard... so i grounded the rabs wire and got a 4 count from the flash out code.. the book says four flashes = rabs valve switch is closed... what does this mean??? and how can i fix it? i would like to just buy a new valve but they are about 200.00 refurbished.. 1989 fsb 351w v8 thanks guys ...
 

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Driving Stuff Henry Built
-90 xlt, 351w, e4od, man 1356, 3.55, sag, warn hubs, 35s. -73, 400, np435, d20j twin, 35s
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8,067 Posts
Just to confirm, that's 3 short flashes & 1 long flash making 4 total? There's more testing to pinpoint the exact issue once you have the code.
From the 1990 Service Manual:
Flashout Code 4
Yellow REAR ANTILOCK Light Flashes 4 Times
Red Brake Warning Light Illuminated
RABS Valve Switch Closed
4a -Check for closed RABS valve switch
1-Disconnect RABS valve harness connector from valve connector.
2- Place ohmmeter on the 20k ohms scale.
3-Check resistance between valve connector switch pin & valve body.

Valve connector -Pin View

. . . . . . . . . . . .. . . ._____
. . . . . . . . . . . . .. ./>. O.>.\
Valve switch pin ---l-O . >.O>l
. . . . . . . . . . . . . .l . ..O. .. .l
. . . . . . . . .__l__. .l________l
. . . . . . . . . . . .____
. . . . . . . . . . . . ._

Resistance is greater than 10k ohms = Go to test 4b.
Resistance is less than 10k ohms = Replace RABS valve

4b Check for short between RABS ground switch & valve ground lead
1- Set the ohmmeter on 20k ohm scale.
2- Check resistance between the valve connector switch pin and valve solenoid ground pin.

Valve connector -Pin View

. . . . . . . . . . . .. . . ._____
. . . . . . . . . . . . .. ./>. O.>.\
Valve switch pin ---l-O . >.O>l
. . . . . . . . . . . . . .l . ..O----l---- Valve solenoid ground pin
. . . . . . . . . . . . . .l________l

Resistance is greater than 10k ohms = Go to test 4c.
Resistance is less than 10k ohms = Replace RABS valve

4c Check for rabs valve switch wire shorted to ground or module
1- Disconnect battery.
2- Set the ohmmeter on the 200k ohm scale.
3- Disconnect the module harness from the module.
4- Check the resistance between harness connector pin 6 and chassis ground.

Module harness connector -Pin view

__________________________
l.........................................l
l...14 13 12 . . . . . . 11 10 9?..l
l...O . O .O . . . . . . .O . O O...l
l ........................................l
l...O . O .O . O .O . O .O . O. ..l
l...8 . 7 . 6 . 5 . 4 . 3 . 2 . 1....l
\ ....................................../
..\______________________/


Resistance is greater than 100k ohms = Replace computer module.
Resistance is less than 100k ohms = Repair short in 535 circuit, valve switch wire from valve to computer module.
 
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