Circuit Description
The Powertrain Control Module(PCM) continuously monitors the oxygen sensor (O2S 1) activity for 100 seconds. During the monitor period, the PCM counts the number of times that the O2S 1 switches from rich to lean and from lean to rich and adds the amount of time that the O2S 1 took to complete all of the switches. With this information, you can determine an average time for all of the switches. If the average time to switch is too slow, a DTC P0133 will set.
Do not attempt to repair the oxygen sensor. Replace the entire O2S 1 assembly if the following conditions exist:
| • | Any damaged wiring |
| • | A damaged electrical connector |
| • | Any damaged terminals |
Conditions For Running The DTC
| • | The following DTCs are not set: P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441. |
| • | The engine coolant temperature (ECT) is more than 75°C (167°F). |
| • | The engine speed is between 1800 RPM and 2300 RPM. |
| • | The engine is operating in closed loop. |
| • | The throttle position (TP) angle is between 8% percent and 15 percent. |
| • | The evaporative emissions (EVAP) control system is commanded open for more than 80 percent. |
| • | The purge learned memory is more than approximately 0.86. |
| • | The diagnostic completes when 30 seconds accumulated time has been spent in the above conditions. |
Conditions For Setting The DTC
The average O2S 1 response times are more than 249 mS for rich to lean sweeps or 249 mS for lean to rich sweeps.
OR:
The ratio of response times is more than 6.0 or less than 0.2.
Action Taken When the DTC Sets
| • | The Malfunction Indicator Lamp (MIL) will illuminate after 2 consecutive ignition cycles in which the diagnostic runs with the malfunction present. |
| • | The PCM will record the operating conditions at the time that the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers. |
| • | A history DTC stores. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm up cycles without a fault. |
| • | Use a scan tool to clear the DTCs. |
Diagnostic Aids
A DTC P0133 or a slow response is most likely caused by one of the following conditions:
| • | The system will go rich if the fuel pressure is too high. The PCM can compensate for some increase. However, if the pressure rises too much, a DTC P0133 may set. Refer to Fuel System Diagnosis . |
| • | A leaking or malfunctioning fuel injector can cause the system to go rich. |
| • | A manifold absolute pressure (MAP) sensor output that causes the PCM to sense a higher than normal manifold pressure (low vacuum) can cause the system to go rich. Disconnecting the MAP sensor will allow the PCM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is corrected while the sensor is disconnected. |
| • | Check for a leaking fuel pressure regulator diaphragm by checking for the presence of liquid fuel in the vacuum line to the regulator. |
| • | An intermittent TP sensor output can cause the system to go rich due to a false indication of the engine accelerating. |
| • | Inspect the O2S 1 for silicone contamination from fuel or use of an improper RTV sealant. The sensor may have a white powdery coating and result in a high but false voltage signal (rich exhaust indication). The PCM will then reduce the amount of fuel delivered to the engine causing a severe surge or driveability problem. |
An intermittent could be the result of the following conditions:
| • | A poor electrical connection |
| • | Any moisture in the connector or the wiring |
| • | A rubbed-through wire insulation |
| • | A broken wire inside of the insulation |
Inspect for a poor electrical connection or a damaged harness. Inspect the harness electrical connectors for the following conditions:
| • | Any incorrect mating |
| • | Any broken locks |
| • | Any improperly formed electrical connectors |
| • | Any damaged terminals |
| • | A poor terminal-to-wire connection |
| • | A damaged harness |
Do not attempt to repair the oxygen sensor. Replace the entire O2S 1 assembly if the following conditions exist:
| • | Any damaged wiring |
| • | A damaged electrical connector |
| • | Any damaged terminals |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
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When the system is operating correctly the O2S voltage should toggle above and below the specified values.
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The specified value is what is measured on a correctly operating system.
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The specified value is what is measured on a correctly operating system.
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The replacement PCM must be reprogrammed and the Crankshaft Position System Variation Learn procedure must be preformed.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | |||||||
|
Important:: If any other DTCs are set, refer to the other DTCs before proceeding with this table.
Is the voltage outside the specified range? | 400-500 mV | Go to Step 3 | Go to Step 4 | |||||||
3 | Operate vehicle within the Failure Records conditions. Does this DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||
4 | Inspect and test for the following:
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 5 | ||||||
Does the voltage approximately equal the specified value? | 450 mV | Go to Step 6 | Go to Step 8 | |||||||
Does the voltage approximately equal the specified value? | 0 mV | Go to Step 9 | Go to Step 7 | |||||||
7 | Test the low circuit for an open or a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 | ||||||
8 | Test the signal circuit for an open or a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 | ||||||
9 | Inspect for poor connections at the O2S 1. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 | ||||||
10 |
Important:: Determine the cause of contamination before replacing the sensor. Inspect and test for the following:
Replace the O2S 1. Refer to Oxygen Sensor Replacement . Did you complete the repair? | -- | Go to Step 13 | -- | ||||||
11 | Inspect for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 | ||||||
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Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the repair? | -- | Go to Step 13 | -- | |||||||
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
