Otc C0040 Rf Wheel Speed Circuit Malfunction - GMC chevrolet camaro 2000 Service Manual

5-136 Antilock Brake System
DTC C0040 RF Wheel Speed Circuit Malfunction
RF Wheel
Speed
Sensor
@11
0.8 LT BLU 872
8
0.8YEL 833
0.50K GAN 872 0.5 TAN 833
3 5 C1
(ABS)
4 5 C1
(ABS!TCS)
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.Ele.ct.ron.lc Brak .. e
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High
I Control Module
I . . . · .
Low .
I (EBCM)
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RFWheel . .
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A .
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Speed Sensor · ·
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Brakes
519701
Circuit Description • Th.e following conditions may cause an intermittent
The speed sensor used on this vehicle is a multiple
pole magnetic pickup. This sensor produces an
AC signal that the EBCM uses the frequency from to
calculate the wheel speed.
· malfunction:
- A poor connection
- Rubbed-through wire insulation
- A bmken wire inside the insulation
(
Conditions for Setting the DTC
The DTC can be set any time the ignition is in the
RUN position and the EBCM detects an open or
a
If the customer's comme,:its reflect that the amber
ABS!TyS indicator is ononly durk1g moist (
environmental conditions (rain, 'snow, vehicle
a short to voltage.
Action Taken When the DTC Sets
• A malfunction DTC stores.
• The ABS!TCS disables.
• The amber ABS!TCS indicator(s) turn on.
" The Red BRAKE Warning indicator could turn on.
Conditions for Clearing the DTC
• The condition responsible for setting the DTC no
longer exists and the scan tool Clear DTCs
function is used.
• 100 ignition cycles pass with no DTC(s) detected.
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.
• Thoroughly inspect any circuitry that may.be
causing the complaint for the following conditions:
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Poor terminal-to-wiring connections
- Physical damage to the wiring harness
wash), inspect all the wheel speed sensor circuitry
for signs of water intrusion. If the DTC is not
current,clear all DTCs 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 DTC returns, replace the suspected
harness.
O
If an intermittent malfunction exists refer to
Testing for Intermittent and Poor Connections in
Wiring Systems.
Front Wheel Speed Sensor Resistance
Use the following table that contains resistance values
for the front wheel speed sensors at varying sensor
temperatures for use in diagnosis. The values are
approximate and should be used as a guideline
tor diagnosis Refer to ABS Diagnostic Specifications.
Test Description
The numbers below refer to step numbers on the
diagnostic table.
6. This step checks for an open in the WSS or
WSS CKT.
13.
Checks for a short to voltage in the WSS CKT.
15. Checks for a short to voltage in the WSS CKT.