DTC Advanced Diagnostics: P0140
DTC P0140:Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Circuit No Activity

General Description

In order to ensure a constant and appropriate operating temperature of the secondary heated oxygen sensor (secondary HO2S (sensor 2)), a heater is integrated and it is controlled and monitored by the powertrain control module (PCM). The PCM monitors the correlation between the ceramics temperature and internal resistance. In case of defective sensor heating, the ceramics temperature usually is lower compared to a faultless sensor and as a consequence the internal resistance of the sensor is considerably higher compared to a regularly heated sensor. If the secondary HO2S (sensor 2) internal resistance exceeds a specified value for a specified time, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
2 minutes or more
DTC Type
Two drive cycles, MIL on

Enable Conditions
Condition
Minimum
Maximum
Engine stop time
2 minutes
–
Intake air temperature [IAT Sensor (1)]
18.5 °F (-7.5 °C)
–
Exhaust gas temperature
392.02 °F (200.01 °C)
1,111.98 °F (599.99 °C)
12 volt battery voltage [Battery]
10.7 V
16.1 V
[ ]: HDS Parameter

Malfunction Threshold
The secondary HO2S (sensor 2) internal resistance exceeds 1,026 ? - 22,320 ?*.

*: Depends on operating condition

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
Secondary HO2S (sensor 2) resistance high
Secondary HO2S (sensor 2) failure

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.