Circuit Description
The 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 in order 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.
Replace the entire oxygen sensor (O2S 1) assembly (Do not attempt to repair the oxygen sensor) if the following conditions exist:
| • | Damaged wiring |
| • | Damaged electrical connector |
| • | Damaged terminal(s) |
Conditions for Running The DTC
| • | DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 not set. |
| • | ECT is greater than 75°C (167°F). |
| • | Engine speed is between 1,800 RPM and 2,300 RPM. |
| • | Engine operating in closed loop. |
| • | Throttle Position (TP) angle is between 8% and 15%. |
| • | Evaporative emissions control system is commanded open for greater than 80%. |
| • | Purge learned memory is greater than approximately 0.86. |
| • | 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 greater than 249mS for rich to lean sweeps or 249mS for lean to rich sweeps.
Or
Ratio of response times is greater than 6.0 or less than 0.2.
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate after two 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 three 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. |
| • | The MIL/DTCs can be cleared by using the scan tool. |
Diagnostic Aids
DTC P0133 or a slow response is most likely caused by one of the following conditions:
| • | The fuel pressure--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 high, a DTC P0133 may set. See Fuel System Diagnosis . |
| • | A leaking fuel injector--A leaking or malfunctioning fuel injector can cause the system to go rich. |
| • | The MAP sensor--An 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 no longer present while the sensor is disconnected. |
| • | The fuel pressure regulator--Check for a leaking fuel pressure regulator diaphragm by checking for the presence of liquid fuel in the vacuum line to the regulator. |
| • | The TP sensor--An intermittent TP sensor output can cause the system to go rich due to a false indication of the engine accelerating. |
| • | The O2S 1 contamination--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:
| • | Poor electrical connection |
| • | Moisture in the connector/wiring |
| • | Rubbed through wire insulation |
| • | Broken wire inside of the insulation |
Check for a poor electrical connection or a damaged harness. Inspect the harness electrical connectors for the following conditions:
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed electrical connectors |
| • | Damaged terminals |
| • | A poor terminal to wire connection |
| • | A damaged harness |
Replace the entire oxygen sensor (O2S 1) assembly (Do not attempt to repair the oxygen sensor) if the following conditions exist:
| • | Damaged wiring |
| • | Damaged electrical connector |
| • | Damaged terminal(s) |
Test Description
The number(s) below refer(s) to the step number(s) on the Diagnostic Table.
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The Powertrain OBD System Check prompts the technician to complete some of the basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information then stores in the scan tool for later reference.
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Reprogram the replacement PCMs and perform the crankshaft position system variation procedure. Refer to the latest Techline information for PCM programming and the Crankshaft Position System Variation Learn for the crankshaft position system variation learn procedure.
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If no malfunctions have been found at this point and no additional DTCs were set, refer to the Diagnostic Aids for additional checks and information.
Step | Action | Value(s) | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | |||||||||||||
2 |
Were there any component DTCs set? | -- | Go to Component DTC tables | |||||||||||
3 |
Do the parameters show averages less than the specified values or ratios less than or greater than the specified values? | 249 ms 249 ms 0.2 6.0 | ||||||||||||
4 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.
Was a problem found in any of the above areas? | -- | ||||||||||||
5 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Was a repair necessary? | -- | ||||||||||||
6 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Does the scan tool voltage indicate voltage within specified values? | 407-509 mV | ||||||||||||
7 |
Does the scan tool voltage indicate the voltage below the specified value? | 200 mV | ||||||||||||
8 |
Notice: Determine and correct the cause of the contamination in order to prevent damage to the replacement sensors.
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Is the action complete? | -- | -- | |||||||||||
9 | Repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||||||||
10 |
Is the action complete? | -- | -- | |||||||||||
11 |
Does the O2S 1 voltage measure above the specified value? | 407 mV | ||||||||||||
12 |
Was repair necessary? | 5ohms | ||||||||||||
13 |
Was a repair necessary? | 5ohms | ||||||||||||
14 |
Did the terminal require replacement? | -- | ||||||||||||
15 |
Did the terminal require replacement? | -- | ||||||||||||
Replace the PCM. Refer to the Powertrain Control Module Replacement . Is the action complete? | -- | -- | ||||||||||||
17 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||||||||||||
Check to see if any additional DTC are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to applicable DTC table | System OK |
