DTC Advanced Diagnostics: P0140 (3.0L Engine)
DTC P0140: Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Circuit No Activity
General Description
The element impedance of the secondary heated oxygen sensor (secondary HO2S (sensor 2)) is monitored to determine whether the secondary HO2S (sensor 2) is active or not. The element temperature can be derived from the element impedance, and it is used for the malfunction detection. If the element temperature of the secondary HO2S (sensor 2) does not reach to a certain value after certain duration has passed since the heater is on, the powertrain control module (PCM) detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 10 seconds or more |
| DTC Type | Two drive cycles, MIL on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time after the secondary HO2S (sensor 2) heater is on | 3 minutes 10 seconds | - |
| Fuel feedback | Other than during fuel cut-off operation | |
Malfunction Threshold
The element temperature of the secondary HO2S (sensor 2) does not reach 1, 022 deg.F (550 deg.C) for at least 10 seconds even after 3 minutes 10 seconds has passed from the heater on.
Possible Cause
- Secondary HO2S (sensor 2) failure
Confirmation Procedure
Operating Condition
Start the engine, and let it idle until the radiator fan comes on.
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, the freeze data, and the on-board snapshot 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, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.