Dtc C0056 Rear Wheel Speed Ckt Range/Performance - GMC chervolet camaro 1999 Service Manual

Brakes Antilock Brake System 5-159
DTC C0056 Rear Wheel Speed CKT Range/Performance
Rear
Wheel
0.5WHT
C405C
C405B
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885
D• 01
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0.35 RED 885
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A 884
c
C1
C200D
A14 C200A
Circuit Description
The speed sensor used on this vehicle is a single
point magnetic pickup. This sensor produces an AC
signal that the EBCM uses the frequency from to
calculate the wheel speed.
Conditions for Setting the DTC
• The DTC will set if one wheel speed = 0 and the
other WSS are greater than 40 Km/h (25 mph)
for 1 O ms, or if the EBCM detects a short to
ground.
• The DTC will set if during drive off, one wheel
speed= 0, and the other WSS are greater than
12 Km/h (7.5 mph).
Action Taken When the DTC Sets
• A malfunction OTC stores.
• The ABS disables.
• The amber ABS indicator turns on.
• The Red BRAKE Warning indicator turns on.
Conditions for Clearing the DTC
• The condition responsible tor setting the OTC no
longer exists and the scan tool Clear OTCs
function is used.
• 100 ignition cycles pass with no OTC(s) detected.
Important: After the OTC is cleared by ignition
cycle default, the vehicle must be driven above
12 Km/h (8 mph) tor the ABS/TCS indicator(s) to
turn off.
Diagnostic Aids
• It is very important that a thorough inspection of
the wiring and connectors be performed. Failure
to carefully and fully inspect wiring and connectors
may result in misdiagnosis, causing part
replacement with reappearance of the malfunction.
22 23
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Electronic Brake
I
H i g h ~
I
Control Module
I
Low
I (EBCM)
I
Rear
Wheel
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:&
I
Speed
Sensor -=-
I .- .....
Signal
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213280
• Thoroughly inspect any circuitry that may .be
causing the complaint tor the following conditions:
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Poor terminal-to-wirin,g connections
- Physical damage to the wiring harness
• The following conditions may cause an intermittent
malfunction:
- A poor connection
- Rubbed-through wire insulation
- A broken wire inside the insulation
• If the customer's comments reflect that the amber
ABS indicator is on only during moist
environmental conditions (rain, snow, vehicle
wash), inspect all the wheel speed sensor circuitry
for signs of water intrusion. If the OTC is not
current, clear all OTCs and simulate the effects of
water intrusion by using the following procedure:
1. Spray the suspected area with a five
percent saltwater solution.
Add two teaspoons of salt to twelve ounces
of water to make a five percent saltwater
solution.
2. Test drive the vehicle over various road
surfaces (bumps, turns, etc.) above 40 km/h
(25 mph) for at least 30 seconds.
3. If the OTC returns, replace the suspected
harness.
• If an intermittent malfunction exists refer to
Troubleshooting Procedures Cell 4 in Electrical
Diagnosis for further diagnosis.