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.

Turn the ignition on.

With the scan tool, record and erase DTCs.

Road test the vehicle over 40 km/h (25 mph).

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

With the scan tool, read DTCs.

NOTE: The Anti-Lock Brake Module must sense ALL 4 wheels at 12 km/h (7.5 mph) before it will extinguish the ABS indicators.

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

Yes
1. Go To Step 2).
No
1. The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
2. Refer to the ABS-INTERMITTENT CONDITION TEST. (Refer to BRAKES - DIAGNOSIS AND TESTING - ABS-INTERMITTENT CONDITION) .
2) CHECK WHEEL SPEED SENSOR SIGNALS
Turn the ignition on.

With the scan tool, monitor and graph ALL the WSS speeds and compare graph while an assistant drives the vehicle.

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

Slowly accelerate as straight as possible from a stop to 40 km/h (25 mph).

Is the Left Front WSS speed showing 0 km/h (0 mph) or not matching other wheel speeds?

Yes
1. Go To Step 3).
No
1. Refer to the INTERMITTENT CONDITION diagnostic procedure. (Refer to BRAKES - DIAGNOSIS AND TESTING - ABS-INTERMITTENT CONDITION) .
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST) .
3) CHECK FOR IMPROPER LEFT FRONT TIRE PRESSURE/MISMATCHED TIRES
Turn the ignition off.

Check and adjust the Left Front Tire pressure.

Check and adjust all other tire pressures.

Inspect for mismatched tires on vehicle.

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

Yes
1. Repair as necessary
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST) .
No
1. Go To Step 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

Inspect the Anti-Lock Brake Module harness connector, Left Front WSS, and Left Front WSS harness connector

Inspect the Left Front WSS for looseness, excessive corrosion and not properly fastened.

Inspect the (B8) Left Front WSS Signal and (B9) Left Front WSS Supply circuits between the Left Front WSS and Anti-Lock Brake Module for damage.

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

Yes
1. Repair as necessary
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST) .
No
1. Go To Step 5).
5) CHECK LEFT FRONT TONE WHEEL FOR DAMAGE
Inspect the Left Front Tone Wheel for damage, missing teeth, cracks, or looseness.

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

Is the Left Front Tone Wheel damaged?

Yes
1. Repair as necessary
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST) .
No
1. Go To Step 6).
6) CHECK LEFT FRONT WHEEL BEARING FOR DAMAGE
Inspect the Left Front wheel bearing for excessive runout or clearance.

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

Is the Left Front Wheel Bearing Damaged?

Yes
1. Repair as necessary
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST) .
No
1. Go To Step 7).
7) LEFT FRONT WHEEL SPEED SENSOR
Replace the Left Front Wheel Speed Sensor in accordance with the Service Information.

Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST) .

Road test the vehicle over 40 km/h (25 mph).

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

With the scan tool, read ABS DTCs.

NOTE: The Anti-Lock Brake Module must sense ALL 4 wheels at 12 km/h (7.5 mph) before it will extinguish the ABS indicators.

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

Yes
1. Replace the Anti-Lock Brakes Module in accordance with the Service Information.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST) .
No
1. Test Complete.