DTC P0159: General Description
The front secondary heated oxygen sensor (secondary HO2S (bank 2, sensor 2)) detects the oxygen content in the exhaust gas downstream of the front warm up three way catalytic converter (WU-TWC) (bank 2) during stoichiometric air/fuel ratio feedback control. The powertrain control module (PCM) controls the air/fuel ratio with the front air/fuel ratio (A/F) sensor (bank 2, sensor 1) output voltage to optimize the front WU-TWC (bank 2)'s efficiency. When the front secondary HO2S (bank 2, sensor 2) does not change during lean air/fuel ratio when the throttle is closed, after full current is applied to the front secondary HO2S (bank 2, sensor 2) heater, and output remains within the specified range continuously, the PCM detects a malfunction and stores a DTC.