Jeep Liberty KJ. Manual — part 575
7.
CHECK (B8) LEFT FRONT WSS SIGNAL CIRCUIT FOR A SHORT TO GROUND
Turn the ignition off.
If not done so previously, disconnect the Anti-Lock Brakes Module har-
ness connector.
Using a 12-volt test light connected to 12 volts, probe the (B8) Left
Front WSS Signal circuit.
Does the test light illuminate?
Yes
>> Repair the (B8) Left Front WSS Signal circuit for a short to
ground.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
No
>> Go To 8
8.
CHECK (B8) LEFT FRONT WSS SIGNAL CIRCUIT FOR AN OPEN
Connect a jumper wire between ground and the (B8) Left Front WSS
Signal circuit in the Anti-Lock Brakes Module harness connector.
Using a 12-volt test light connected to 12 volts, probe the (B8) Left
Front WSS Signal circuit.
Does the test light illuminate brightly?
Yes
>> Go To 9
No
>> Repair the (B8) Left Front WSS Signal circuit for an open.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
9.
CHECK (B8) LEFT FRONT WSS SIGNAL CIRCUIT FOR A SHORT TO (B9) LEFT FRONT WSS 12 VOLT
SUPPLY CIRCUIT
If not done so previously, remove all jumper wires.
Measure the resistance between the (B8) Left Front WSS Signal circuit
and the (B9) Left Front WSS 12 Volt Supply circuit.
Is the resistance below 10k ohms?
Yes
>> Repair the (B8) Left Front WSS Signal circuit for a short to
the (B9) Left Front WSS 12 Volt Supply circuit.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
No
>> Go To 10
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KJ
10.
CHECK LEFT FRONT WSS
Reconnect the Anti-Lock Brakes Module harness connector.
Turn the ignition on.
Measure the voltage of the (B9) Left Front WSS 12 Volt Supply circuit
while reconnecting the Left Front WSS harness connector.
Did the voltage drop to 0 volts?
Yes
>> Replace the Left Front WSS in accordance with the Service
Information.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
No
>> Go To 11
11.
CHECK LEFT FRONT WSS OUTPUT
Backprobe the (B8) Left Front WSS Signal circuit in the Left Front WSS
harness connector with the positive lead of an ammeter.
Connect the ammeter negative lead to a good clean chassis ground.
Slowly rotate the left front wheel.
Does the amperage reading toggle between 7 mA and 14 mA?
Yes
>> Replace the Anti-Lock Brakes Module in accordance with
the Service Information.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
No
>> Replace the Left Front WSS in accordance with the Service
Information.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
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BRAKES - ABS ELECTRICAL DIAGNOSTICS
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C1011–LEFT FRONT WHEEL SPEED SENSOR SIGNAL ERRATIC PERFORMANCE
For a complete wiring diagram Refer to Section 8W.
•
When Monitored:
With the ignition on.
•
Set Condition:
If the Anti-Lock Brakes Module receives either an intermittent signal from the Left Front WSS at a vehicle
speed above 35 km/h (22 m.p.h.), or an erratic signal from the Left Front WSS during acceleration, or it
senses that the left front wheel speed is different from other wheels.
Possible Causes
LEFT FRONT WSS LOOSE
LEFT FRONT WSS CIRCUITS, CONNECTORS, TERMINALS DAMAGED
LEFT FRONT TONE WHEEL DAMAGED OR WRONG NUMBER OF TEETH
EXCESSIVE AIR GAP BETWEEN LEFT FRONT WSS AND TONE WHEEL
LEFT FRONT WHEEL BEARING DAMAGED
LEFT FRONT BRAKE HARDWARE DAMAGED
LEFT FRONT WSS
ANTI-LOCK BRAKES MODULE
Diagnostic Test
1.
VERIFY IF DTC C100A–LEFT FRONT WHEEL SPEED SENSOR CIRCUIT IS ACTIVE
Turn the ignition on.
With the scan tool, record and erase ABS DTCs.
Cycle the ignition switch.
With the scan tool, read ABS DTCs.
NOTE: The Anti-Lock Brake Module must sense all 4 wheels at 25 km/h (15 m.p.h.) before it will extinguish
the ABS Indicator.
Does the scan tool display: C100A–LEFT FRONT WHEEL SPEED SENSOR CIRCUIT?
Yes
>> Diagnose and repair the DTC. Refer to the Table of Contents in this Section for a complete list of symp-
toms.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
No
>> Go To 2
2.
COMPARE WHEEL SPEED SENSOR SIGNALS
WARNING: Ensure brake capability is available before road testing.
With the scan tool, monitor ALL WSS speeds while an assistant drives the vehicle.
Slowly accelerate as straight as possible from a stop to 40 km/h (25 m.p.h.).
Is the Left Front WSS speed showing 0 km/h (0 m.p.h.) or not matching other wheel speeds?
Yes
>> Go To 3
No
>> Perform the ABS Intermittent Condition diagnostic procedure in this Section.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
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3.
INSPECT LEFT FRONT WSS, WIRE HARNESS, CONNECTORS & TERMINALS
Turn the ignition off.
Inspect the Anti-Lock Brakes Module harness connector, Left Front WSS connector, and Left Front WSS harness
connector for broken, bent, pushed out, and corroded terminals.
Verify that the Left Front WSS is properly installed and fastened.
Inspect the Left Front WSS wire harness between the sensor and the Anti-Lock Brakes Module for damage.
Were any problems found?
Yes
>> Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
No
>> Go To 4
4.
INSPECT LEFT FRONT TONE WHEEL
Inspect the tone wheel for damage, missing teeth, cracks, and looseness. The teeth must be perfectly square, not
bent, or nicked.
Is the tone wheel damaged?
Yes
>> Replace the Left Front Tone Wheel in accordance with the Service Information.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
No
>> Go To 5
5.
CHECK LEFT FRONT WSS AIR GAP
Using a feeler gauge, measure the Left Front WSS air gap.
NOTE: Refer to the appropriate service information for procedures and specifications.
Is the Left Front WSS air gap within specifications?
Yes
>> Go To 6
No
>> Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
6.
CHECK LEFT FRONT WHEEL BEARING FOR DAMAGE
Check the left front wheel bearing for excessive runout and clearance.
NOTE: Refer to the appropriate service information for procedures and specifications.
Is the left front wheel bearing damaged?
Yes
>> Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
No
>> Go To 7
7.
CHECK LEFT FRONT BRAKE HARDWARE FOR DAMAGE
Visually inspect the left front brake linings for contamination and overheating. Check for dragging, bent, and seized
components and hardware.
Is any brake lining, component, or hardware damaged?
Yes
>> Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1. (Refer to 5 - BRAKES - STANDARD PROCEDURE).
No
>> Go To 8
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