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DTC Advanced Diagnostics: P0133
DTC P0133:Air/Fuel Ratio (A/F) Sensor (Sensor 1) Malfunction/Slow Response
General Description
The powertrain control module (PCM) monitors the air/fuel ratio (A/F) sensor (sensor 1) for slow response malfunctions. Aging and contamination of the A/F sensor (sensor 1) can slow down the sensor response rate. A dynamically slow signal can lead to increased exhaust emissions.
When enable conditions are met and catalyst is purged with the rich mixture (rich conditioning phase), the monitor switches to the lean mixture where the measurement of catalyst oxygen storage capacity is carried out (oxygen storage capacity (OSC) measurement). At the beginning of this state the delay time values as well as the gradients of A/F sensor (sensor 1) signal are evaluated (rich-to-lean transition). After OSC measurement is finished a rich operation state is commanded. At the beginning of this state the delay time values as well as the gradients of A/F sensor (sensor 1) signal are evaluated (lean-to-rich transition). If the delay time or transition time is a specified value, 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
Step response measurement
|
Condition |
Minimum |
Maximum |
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Time not in fuel cut-off operation |
10 seconds |
– |
|
Outside air temperature |
-54 °F (-48 °C) |
– |
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Engine coolant temperature [ECT sensor 1] |
-54.47 °F (-48.04 °C) |
– |
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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) |
– |
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Relative air charge |
13 % to 22 % |
– |
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Other |
Exhaust gas mass flow is stable for at least 1 second |
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Actual secondary HO2S (sensor 2) heater temperature is around set point temperature |
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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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Canister not purging | |
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Table A for step response measurement
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Condition |
Minimum |
Maximum |
|
Catalyst bed temperature |
842 °F (450 °C) |
1,562 °F (850 °C) |
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Exhaust gas mass flow |
20 kg/h (44 lbs/h) |
200 kg/h (441 lbs/h) |
|
Commanded lambda |
0.97 |
1.03 |
|
Other |
Catalyst bed temperature is stable | |
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Identification
|
Condition |
Minimum |
Maximum |
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Elapsed time after starting the engine |
7 seconds |
– |
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Elapsed time after the A/F sensor (sensor 1) is active |
10 seconds |
– |
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Time not in fuel cut-off operation |
3 seconds |
– |
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Time not gear shifted |
0.15 seconds |
– |
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Time lambda closed control |
2 seconds |
– |
|
Vehicle speed [Vehicle Speed] |
0 mph (0 km/h) |
– |
|
Rate of change of modeled lambda |
0.02 |
– |
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Other |
No transition time faults are detected during step response measurement | |
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Malfunction Threshold
Any of the conditions is met:
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Step response measurement |
|
|
? |
The average value of delay time in lean-to-rich direction is more than 0.5 second at least 3 fault confirmations. | |
|
|
? |
The average value of delay time in rich-to-lean direction is more than 0.5 second at least 3 fault confirmations. | |
|
|
? |
The average value of transition time in lean-to-rich direction is greater than 0.5 second at least 3 fault confirmations. | |
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|
? |
The average value of transition time in rich-to-lean direction is greater than 0.5 second at least 3 fault confirmations. |
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Identification |
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|
? |
The delay time in lean-to-rich direction is more than 1 second. | |
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|
? |
The delay time in rich-to-lean direction is more than 1 second. | |
|
|
? |
The transition time in lean-to-rich direction is more than 1 second. | |
|
|
? |
The transition time in rich-to-lean direction is more than 1 second. | |
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|
? |
The sum of delay and transition time in lean-to-rich direction is more than 1 second. | |
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|
? |
The sum of delay and transition time in rich-to-lean direction is more than 1 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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A/F sensor (sensor 1) deterioration |
Confirmation Procedure
Operating Condition
|
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. | 