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DTC Advanced Diagnostics: P0139
DTC P0139:Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) Slow Response
General Description
The powertrain control module (PCM) monitors the secondary heated oxygen sensor (secondary HO2S (sensor 2)) responsiveness. If the transition time or delay time to go from lean mixture to rich mixture or from rich mixture to lean mixture is too slow, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
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Execution |
Once per driving cycle |
|
Sequence |
None |
|
Duration |
0.5 second or more |
|
DTC Type |
Two drive cycles, MIL on | |
|
Enable Conditions
|
Condition |
Minimum |
Maximum |
|
Time not in fuel cut-off operation |
10 seconds |
– |
|
Outside air temperature |
-54.4 °F (-48 °C) |
– |
|
Engine coolant temperature [ECT Sensor 1] |
-54.47 °F (-48.04 °C) |
– |
|
Catalyst temperature |
842 °F (450 °C) |
– |
|
Engine speed [Engine Speed] |
1,200 rpm |
4,520 rpm |
|
Barometric pressure [Baro Sensor] |
739 hPa (555 mmHg, 21.8 inHg) |
– |
|
Vehicle speed [Vehicle Speed] |
0 mph (0 km/h) |
– |
|
Charging efficiency |
13.008 % to 22 % |
– |
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Other |
Following table A must be met for more than 0.08 kg (0.18 lbs) of integrated exhaust gas mass flow |
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Exhaust gas mass flow is stable for at least 1 second |
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Canister not purging |
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No gear shifting |
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A/F sensor (sensor 1) is ready for operation |
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Actual temperature is around set point temperature | |
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Table A
|
Condition |
Minimum |
Maximum |
|
Catalyst bed temperature |
842 °F (450 °C) |
1,562 °F (850 °C) |
|
Exhaust gas mass flow |
20 kg/h (44 lbs/h) |
200 kg/h (441 lbs/h) |
|
Commanded lambda |
0.97 |
1.03 |
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Other |
Catalyst bed temperature is stable | |
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Malfunction Threshold
Any of the conditions occur:
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The transition time of secondary HO2S (sensor 2) voltage at transition from lean mixture to rich mixture is greater than 0.9 second. |
|
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The transition time of secondary HO2S (sensor 2) voltage at transition from rich mixture to lean mixture is greater than 0.75 second. |
|
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The delay time of secondary HO2S (sensor 2) voltage at transition from lean mixture to rich mixture is greater than 0.9 second. |
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The delay time of secondary HO2S (sensor 2) voltage at transition from rich mixture to lean mixture is greater than 0.75 second. |
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.
|
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Secondary HO2S (sensor 2) SO2 failure |
Confirmation Procedure
Operating Condition
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1. |
Start the engine. Hold the engine speed [Engine Speed] at 3,000 rpm without load (in neutral) until the radiator fan comes on. |
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2. |
Drive the vehicle at constant vehicle speed with part load. |
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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. | 