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DTC Advanced Diagnostics: P0154
DTC P0154:Front Air/Fuel Ratio (A/F) Sensor (Bank 2, Sensor 1) Heater System Malfunction
General Description
The front air/fuel ratio (A/F) sensor (bank 2, sensor 1) is activated by warming the element with a heater and by maintaining a steady high temperature to accurately calculate the air/fuel ratio. If the heater does not properly heat the element, the front A/F sensor (bank 2, sensor 1) does not activate, and the exhaust emissions deteriorate. The powertrain control module (PCM) monitors the front A/F sensor (bank 2, sensor 1) internal resistance.
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1. |
When the front A/F sensor (bank 2, sensor 1) does not activate for a set time after the front A/F sensor (bank 2, sensor 1) heater is turned on (with high front A/F sensor (bank 2, sensor 1) internal resistance), a malfunction of the front A/F sensor (bank 2, sensor 1) heater is detected, and a DTC is stored. |
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2. |
When the front A/F sensor (bank 2, sensor 1) heater cycles ON and OFF for a set time, and the resistance remains high when the heater is ON, a malfunction of the front A/F sensor (bank 2, sensor 1) heater is detected, and a DTC is stored. |
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
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Execution |
Continuous |
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Sequence |
None |
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Duration |
40 seconds or more*1
90 seconds or more*2 |
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DTC Type |
Two drive cycles, MIL on |
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OBD Status |
PASSED/FAILED/NOT COMPLETED (STILL TESTING) | |
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Enable Conditions
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Condition |
Minimum |
Maximum |
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Battery voltage [BATTERY] |
10.5 V |
– |
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Fuel feedback |
Other than during fuel cut-off operation |
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No active DTCs set (prevents monitor from running)*3 |
P0155, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0351, P0352, P0353, P0354, P0355, P0356, P1174, P2197, P2240, P2241, P2247, P2249, P2254, P2255, P2652, P2654 |
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No active DTCs set (prevents monitor from running)*4 |
P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0351, P0352, P0353, P0354, P0355, P0356, P1174, P2197, P2652, P2654 | |
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Malfunction Threshold
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Malfunction determination 1 - From start up
The front A/F sensor (bank 2, sensor 1) internal resistance value [AF SENSOR IMPEDANCE] is 200 ? or more for at least 40*1 (90)*2 seconds right after the engine starts. |
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Malfunction determination 2 - Hot
The front A/F sensor (bank 2, sensor 1) internal resistance value [AF SENSOR IMPEDANCE] is 270 ? or more for at least 1.0 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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Front A/F sensor (bank 2, sensor 1) heater failure |
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Front A/F sensor (bank 2, sensor 1) element failure |
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Front A/F sensor (bank 2, sensor 1) VSB2 line open |
Confirmation Procedure
Operating Condition
Start the engine, and let it idle for at least 1 minute. When engine coolant temperature [ECT SENSOR 1] is 14 °F (-10 °C) or less, let the engine idle for at least 4 minutes.
With the HDS
None.
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. |
