P0141
P0141Component Location:
General Description
In order to control emissions of the CO, HC and NOx components of the exhaust gas, heated oxygen sensor (HO2S), mounted on the front side and rear side of catalytic converter, detects the oxygen content in the exhaust gas. The front HO2S signal is used to control air/fuel ratio (closed loop fuel control) and the rear HO2S signal is used to monitor front HO2S and catalyst for proper operation. The HO2S requires a minimum temperature to operate properly and provide a closed loop fuel control system. The HO2S contains the heater element to reduce its warming-up time and ensure its performance during all driving conditions. The ECM controls this heater element by duty cycle. The main relay supplies voltage to the heater and the ECM provides a ground circuit for activating the heater.
DTC Description
If the internal resistance of heater is over the threshold value under enable conditions, PCM sets DTC P0141.
DTC Detecting Condition:
Specification:
Signal Waveform:
Schematic Diagram:
Monitor Scantool Data
1. Connect scantool to DLC (Data Link Cable).
2. Warm up the engine to normal operating temperature.
3. Monitor "HO2S (B1/S2)" parameter on scantool.
4. Is the "HO2S (B1S2)" parameter displayed correctly?
YES - Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure.
NO - Go to "Terminal & Connector Inspection" procedure
Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Power Circuit Inspection" procedure.
Power Supply Circuit Inspection
1. IG "OFF".
2. Disconnect HO2S (B1S2) connector.
3. IG "ON" & ENG "OFF".
4. Measure voltage between terminal 4 of HO2S (B1S2) harness connector and chassis ground.
Specification : B +
5. Is the measured voltage within specification?
YES - Go to "Control Circuit Inspection" procedure.
NO - Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
Control Circuit Inspection
1. IG "OFF".
2. Disconnect HO2S (B1S2) connector.
3. IG "ON" & ENG "OFF"
4. Measure voltage between terminal 3 of HO2S (B1S2) harness connector and chassis ground.
Specification : Approx. 3.5 V
5. Is the measured voltage within specification?
YES - Go to "Component Inspection" procedure.
NO - Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
Component Inspection
1. Check Heater resistance
1. IG "OFF".
2. Disconnect HO2S (B1S2) connector.
3. Measure resistance between terminal 3 and 4 of HO2S (B1S2) connector. (Component Side)
Specification :
4. Is the measured resistance within specification?
YES - Substitute with a known - good ECM and check for proper operation. If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure.
NOTE: There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM. Before or after testing PCM on the vehicle, use this function to reuse the PCM on the others
NO - Substitute with a known - good HO2S and check for proper operation. If the problem is corrected, replace HO2S and go to "Verification of Vehicle Repair" procedure.
Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Clear the DTCs and Operate the vehicle within DTC Enable conditions in General information.
3. Are any DTCs present?
YES - Go to the applicable troubleshooting procedure.
NO - System is performing to specification at this time.