Advanced Diagnostics
Advanced Diagnostics - DTC P0159: Front Secondary Heated Oxygen Sensor (Secondary HO2S (Bank 2, Sensor 2)) Slow Response
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's efficiency. When the front secondary HO2S does not change during lean air/fuel ratio when the throttle is closed, after full current is applied to the front secondary HO2S heater, and output remains within the specified range continuously, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
Enable Conditions
Malfunction Threshold
The front secondary HO2S output voltage is 0.05 V or more for at least 7.0 seconds.
Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on.
2. Drive the vehicle at a steady speed between 55 - 75 mph (88 - 120 km/h) for at least 1 minute.
3. Decelerate with the throttle valve fully closed for at least 7 seconds.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.
Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.