The anti-lock brake (ABS) system in vehicles relies on sensors to operate. These sensors capture the rotation of the wheels, typically through interfacing with a notched sensor ring. If this ring gets damaged, the system will not operate properly. Follow this Real Fix to see diagnosis of ABS codes on this Mercury Mariner lead to a damaged sensor ring and the repair.
Vehicle
2006 Mercury Mariner Base 3.0L
Title
C1233, U0415, U2023, Replaced Axle Shaft
Complaint
The customer states the anti-lock brake system (ABS) light is on.
Cause
Connected a scan tool and found codes: C1233 – Wheel Speed Sensor LF Input Signal Missing; U0415 – Invalid Data Received From Anti-Lock Brake System (ABS) Control Module and U2032 – Fault Received From External Node. Performed a road test, used the scan tool to monitor live data and found the left front ABS wheel speed sensor signal parameter was erratic. Backprobed the left front ABS wheel speed sensor and monitored the sensor signal on a lab scope while spinning the left front wheel by hand. The left front ABS wheel speed sensor produced an erratic signal on the lab scope. Visually inspected the left front wheel speed sensor and wiring harness and found the left front abs sensor ring was damaged. The left front abs sensor ring is integrated into the left front axle shaft and is replaced as a unit.
Correction
Replaced the left front axle shaft, cleared codes, performed a road test and verified the vehicle operated properly.