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EC-252 < DTC/CIRCUIT DIAGNOSIS > [QR25DE] P0139 HO2S2 P0139 HO2S2 DTC Description INFOID:0000000011277991 DTC DETECTION LOGIC The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/F) sensor 1. The oxy- gen storage capacity of the three way catalyst 1 causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the switching response of the sensor's voltage is faster than specified during various driving conditions such as fuel cut. POSSIBLE CAUSE • Harness or connectors (The sensor circuit is open or shorted.) • Heated oxygen sensor 2 • Fuel system • EVAP system • Intake air system FAIL-SAFE Not applicable DTC CONFIRMATION PROCEDURE 1. INSPECTION START Do you have CONSULT? YES >> GO TO 2. NO >> GO TO 7. 2. PRECONDITIONING If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test. 1. Turn ignition switch OFF and wait at least 10 seconds. 2. Turn ignition switch ON. 3. Turn ignition switch OFF and wait at least 10 seconds. TESTING CONDITION: For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30 °C (32 to 86°F). >> GO TO 3. 3. PERFORM DTC CONFIRMATION PROCEDURE With CONSULT 1. Turn ignition switch ON and select “DATA MONITOR” mode of “ENGINE” using CONSULT. 2. Start engine and warm it up to the normal operating temperature. 3. Turn ignition switch OFF and wait at least 10 seconds. 4. Turn ignition switch ON. SEF302U DTC No. CONSULT screen terms (Trouble diagnosis content) DTC detecting condition P0139 HO2S2 (B1) The switching time between rich and lean of a heated oxygen sensor 2 sig- |