Actron GM Code Scanner CP9001 - Manual (Page 86)

86
OF
F ON
SYSTEM 7: Kelsey-Hayes
RWAL
(Rear Wheel Anti-Lock)
1988 Blazer, C & K Series Pickup Truck, Sierra
1989 Astro, Blazer, C & K Series Pickup Truck, Jimmy,
S Series (2 WD) Pickup Truck, Safari, Sierra
1990 Astro, Blazer, C & K Series Pickup Truck,
G Series (RWD) Van, Jimmy, R & V Series Truck,
S & T Series Pickup Truck, Safari, Sierra, Suburban
1991 Astro, Blazer, C & K Series Pickup Truck,
G Series (RWD) Van, Jimmy, R & V Series Truck,
S & T Series Pickup Truck, Safari, Sierra, Suburban
1992 Astro, Blazer, C & K Series Pickup Truck,
G Series (RWD) Van, Jimmy,
S & T Series Pickup Truck, Safari, Sierra
1993 Blazer, C & K Series Pickup Truck, Jimmy,
S & T Series Pickup Truck, Sierra
1994 Blazer, C & K Series Pickup Truck,
S & T Series Pickup Truck
Diagnostic Circuit Check
Complete all steps before reading
trouble codes!
1) Block the wheels, and release the
parking brake. Do not step on the
service brake!
2) Turn the ignition key to the ON
position, but do not start the engine.
Observe the
instrument panel
brake warning light:
• If the brake light
turns ON, and then OFF after about
2 seconds, the self-diagnostic
circuitry has found NO current
problems with the ABS system.
– DO NOT perform ABS code
reading procedure! A false code 9
will be stored in ABS computer
memory if the code reading steps
are followed when no faults currently
exist. (This is a quirk of the RWAL
ABS system.)
– Do this additional check: Step on
the service brake. If the brake
warning light comes ON, there is a
problem with the combination valve.
(This valve is part of the normal
braking system, not part of the anti-
lock braking system.) Release the
service brake.
• If the brake light turns ON and stays
ON (or turns ON after the bulb
check), proceed to the diagnostic
procedure outlined in your vehicle
service manual for the brake light
ON symptom.
• If the brake light stays OFF,
proceed to the diagnostic
procedure outlined in your vehicle
service manual for the brake light
OFF symptom.
• If the brake light is FLASHING,
proceed to READING ABS
CODES, page 85.
3) Turn the ignition key
to the OFF position.