Symptom:
LEFT FRONT SENSOR SIGNAL FAILURE
When Monitored and Set Condition:
LEFT FRONT SENSOR SIGNAL FAILURE
When Monitored:
Wheel speed comparison is checked at drive off or every 7 milliseconds
(ms). Sensor circuit continuity is checked every 7 milliseconds. Wheel speed phase length
supervision is checked every 7 milliseconds.
Set Condition:
If, during an ABS stop, the CAB commands any valve solenoid on for an
extended length of time, and does not see a corresponding wheel speed change, the
Diagnostic Trouble Code (DTC) is set. The DTC can also set if the signal is missing or
erratic.
POSSIBLE CAUSES
LEFT FRONT WHEEL SPEED SENSOR OR CONNECTOR DAMAGED
TONE WHEEL DAMAGED
LEFT FRONT WHEEL SPEED SENSOR AIR GAP OUT OF SPECIFICATION
LEFT FRONT WHEEL BEARING OUT OF SPECIFICATION
LEFT FRONT WHEEL SPEED SENSOR INOPERATIVE
CAB - WON’T RESPOND TO LEFT FRONT WHEEL SPEED SENSOR SIGNAL
INTERMITTENT SIGNAL DTC
TEST
ACTION
APPLICABILITY
1
Turn the ignition on.
Using the DRBIII
t
, monitor the Left Front Wheel Speed Sensor while an assistant
drives the vehicle.
With an assistant to drive, use the DRBIII
t
to monitor all wheel speed sensors.
Slowly accelerate as straight as possible from a stop to 24 km/h (15 mph).
Is Left Front WSS Signal 0 km/h (0 mph) or differing from others by more than 5
km/h (3 mph)?
All
Yes
→
No
→
2
Turn the ignition off.
Inspect the Left Front Wheel Speed Sensor and Connector.
Is the Sensor or Connector Damaged?
All
Yes
→
Repair as necessary. The CAB must sense all four wheels at 25
km/h (15 mph) before it will extinguish the ABS Indicator.
Perform ABS VERIFICATION TEST - VER 1.
No
→
34
BRAKES (CAB)
