Advanced Diagnostics

Advanced Diagnostics - DTC P0158: Front Secondary Heated Oxygen Sensor (Secondary HO2S (Bank 2, Sensor 2)) Circuit High Voltage

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 from the front air/fuel ratio (A/F) sensor (bank 2, sensor 1) output voltage to optimize the front WU-TWC efficiency. After current is applied to the front secondary HO2S heater, if the front secondary HO2S output continues to exceed the upper limit used during feedback control, 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 1.27 V or more for at least 5.0 seconds.

Confirmation Procedure

With the Driving Pattern






1. Start the engine, and let it idle until the radiator fan comes on.
2. Let the engine idle for at least 5 seconds.
3. When the diagnosis does not finish at idle, drive immediately at a steady engine speed between 1,500 - 3,000 rpm for at least 5 seconds.

- When freeze data is stored, drive the vehicle under those conditions instead of Driving Pattern step 3.
- 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.