Vehicle
2018 Ford Fiesta 1.0L Petrol
Title
Code P0141 Replace Oxygen Sensor (B1-S2)
Complaint
The customer states the check engine light is on.
Cause
Connected a scan tool and found code P0141 – O2 Sensor Heater Circuit (Bank 1 Sensor 2). Used the scan tool to monitor the live data, started the vehicle and allowed the engine to obtain the normal operating temperature. Increased the engine speed to 2,000 RPM and observed the oxygen sensor (B1-S2) was fixed and did not change state. Continued to monitor the live data, snapped the throttle and found the oxygen sensor (B1-S2) remained fixed. Performed a visual inspection of the fuses and relays but found no obvious concerns. Visually inspected the oxygen sensor (B1-S2) wiring harness, but found no evidence of any damage. Disconnected the oxygen sensor (B1-S2) harness connector, performed a visual inspection of the terminals and found no visible faults. Key on, used a multi-meter to test for the presence of battery voltage and ground at the oxygen sensor (B1-S2) harness connector and found both were present. Used the multi-meter to measure the resistance of the oxygen sensor (B1-S2) heater element at the oxygen sensor (B1-S2) connector and found the measured resistance was not within the specified range. The results of these tests verified the oxygen sensor (B1-S2) was faulty.
Correction
Replaced the oxygen sensor (B1-S2), cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.