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:
When the Left Front Wheel Speed Sensor (WSS) Signal is intermittently missing while vehicle speed is above 40 km/h (25 mph) or erratic wheel speed signal during acceleration or sensed wheel speed is different from other wheels.

Possible Causes

LEFT FRONT WSS LOOSE — B8, B9 CIRCUITS/CONNECTOR/TERMINAL DAMAGE

LEFT FRONT TONE WHEEL DAMAGE

LEFT FRONT WHEEL/ BEARING DAMAGE

IMPROPER LEFT FRONT TIRE PRESSURE/MISMATCHED TIRES

LEFT FRONT WSS

ANTI-LOCK BRAKE MODULE

Diagnostic Test

1.CHECK FOR DTC C1011-LEFT FRONT WHEEL SPEED SENSOR SIGNAL ERRATIC PERFORMANCE

NOTE: This DTC must be active for the results of this test to be valid.

NOTE: If DTC C100A Left Front Wheel Speed Sensor Circuit is present it must be repaired before continuing.

NOTE: Vehicle must be driven above 40 km/h (25 mph) for set conditions to be met.

Does the scan tool display: C1011-LEFT FRONT WHEEL SPEED SENSOR SIGNAL ERRATIC PERFORMANCE active?

Yes

Go To 3

Go To 2

2.CHECK WHEEL SPEED SENSOR SIGNALS

NOTE: If graph shows periodic dropouts pay close attention to the tone wheel.

Is the Left Front WSS speed showing 0 km/h (0 mph) or not matching other wheels or showing erratic behavior?

Yes

Go To 3

Refer to the ABS-INTERMITTENT CONDITION TEST. (Refer to 5 - BRAKES - DIAGNOSIS AND TESTING)

3.CHECK FOR IMPROPER LEFT FRONT TIRE PRESSURE/MISMATCHED TIRES

Is the Left Front Tire improperly inflated or mismatched tires on vehicle?

Yes

Repair as necessary.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).

Go To 4

4.CHECK LEFT FRONT WSS LOOSENESS, INSPECT B8, B9 CIRCUITS/TERMINALS FOR DAMAGE

NOTE: Check all terminals for broken, bent, pushed out, or corroded terminals

Is the Left Front WSS loose or any of the wiring/connectors/terminals damaged?

Yes

Repair as necessary.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).

Go To 5

5.CHECK LEFT FRONT WHEEL SPEED SENSOR FOR DAMAGE

Is the Left Front Wheel Speed Sensor damaged?

Yes

Replace sensor and hub assembly.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).

Go To 6

6.CHECK LEFT FRONT TONE WHEEL/BEARING FOR DAMAGE

NOTE: The Tone Wheel teeth should be perfectly square, not bent, or nicked.

Is the Left Front Tone Wheel/Bearing damaged?

Yes

Repair as necessary.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).

Go To 7

7.CHECK LEFT FRONT WHEEL BEARING FOR DAMAGE

NOTE: Refer to the appropriate service information, if necessary, for procedures or specifications.

Is the Left Front Wheel Bearing Damaged?

Yes

Repair as necessary.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).

Go To 8

8.LEFT FRONT WHEEL SPEED SENSOR

(Refer to 5 - BRAKES - STANDARD PROCEDURE)

NOTE: Vehicle must be driven above 40 km/h (25 mph) for set conditions to be met.

Did DTC C1011-LEFT FRONT WHEEL SPEED SENSOR SIGNAL ERRATIC PERFORMANCE reset?

Yes

Replace the Anti-Lock Brakes Module in accordance with the Service Information.
Perform ABS VERIFICATION TEST. (Refer to 5 - BRAKES - STANDARD PROCEDURE).

Test Complete.