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P0139, P0159 HO2S2 EC-233 < DTC/CIRCUIT DIAGNOSIS > [VK56DE] C D E F G H I J K L M A EC N P O P0139, P0159 HO2S2 Component Description INFOID:0000000009886643 The heated oxygen sensor 2, after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Even if switching characteristics of the air fuel ratio (A/F) sensor 1 are shifted, the air-fuel ratio is controlled to stoichiometric, by the sig- nal from the heated oxygen sensor 2. This sensor is made of ceramic zirconia. The zirconia generates volt- age from approximately 1V in richer conditions to 0V in leaner condi- tions. Under normal conditions the heated oxygen sensor 2 is not used for engine control operation. On Board Diagnosis Logic INFOID:0000000009886644 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. DTC Confirmation Procedure INFOID:0000000009886645 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. SEF327R SEF302U DTC No. Trouble diagnosis name DTC detecting condition Possible cause P0139 Heated oxygen sensor 2 The switching time between rich and lean of a • Harness or connectors (The sensor circuit is open or shorted) • Heated oxygen sensor 2 P0159 Heated oxygen sensor 2 |