Circuit Description
The PCM continuously monitors the oxygen sensor 1 (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. You can determine a total for all of the switches with this information. If the number of switches is too low, a DTC P1133 will set.
Conditions For Running The DTC
| • | DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set. |
| • | 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 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 of accumulated time has been spent in the above conditions. |
Conditions for Setting the DTC
The number of rich to lean counts is less than 1 or the lean to rich counts is less than 1.
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. |
| • | Use a scan tool to clear the DTCs. |
Diagnostic Aids
DTC P1133 is most likely caused by one of the following:
| • | High fuel pressure -- The system will go rich if fuel pressure is to high. The PCM can compensate for some increase, however, if it the fuel pressure becomes too high, a DTC P0172 will be set. Refer to Fuel System Diagnosis . |
| • | A leaking injector -- A leaking or malfunctioning 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, indicative of a 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 gone while the sensor is disconnected. |
| • | The 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 will cause the system to go rich due to a false indication of the engine accelerating. |
| • | O2S 1 contamination -- Inspect O2S 1 for silicone contamination from fuel or use of improper RTV sealant. The sensor may have a white powdery coating, which may result in a high but false voltage signal, indicating a rich exhaust condition. The PCM will then reduce the amount of fuel that is delivered to the engine, causing a severe surge or driveability problem. |
Test Description
The numbers below refer to the step numbers on the Diagnostic Table.
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The replacement PCM must be programmed and the Crankshaft Position System Variation Learn procedure.
Step | Action | Value(s) | Yes | No | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||||||||||
2 |
Are any component DTCs set? | -- | Go to the applicable DTC | |||||||||||||||
3 |
Important:: The vehicle must be operated within the Conditions for Running the DTC in order for the Rich/Lean and Lean/Rich Transition Data to become active. If not the scan tool will display 0 counts. Does the parameters show fewer transitions than the specified values? | 1-1 | ||||||||||||||||
4 |
Was a problem present 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. Did you find and correct the condition? | -- | ||||||||||||||||
6 |
Does the scan tool voltage indicate the O2S 1 voltage within the specified value? | 407-509 mV | ||||||||||||||||
7 | Connect a jumper wire between the O2S 1 high circuit, on the PCM side of the signal circuit to a ground. Does the scan tool voltage indicate that the O2S 1 voltage is below the specified value? | 200 mV | ||||||||||||||||
8 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Notice: Determine and correct the cause of the contamination in order to prevent damage to the replacement sensors.
Did you complete the replacement? | -- | -- | |||||||||||||||
9 | Repair the condition as necessary. Did you complete repair? | -- | -- | |||||||||||||||
10 |
Did you complete the repair? | -- | -- | |||||||||||||||
11 |
Does the O2S 1 voltage measure above the specified value? | 407 mV | ||||||||||||||||
12 |
Did you complete a repair? | 5ohms | ||||||||||||||||
13 |
Did you complete a repair? | 5ohms | ||||||||||||||||
14 |
Did you find and correct the condition? | -- | ||||||||||||||||
15 |
Did you find and correct the condition? | -- | ||||||||||||||||
|
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 replacement? | -- | -- | ||||||||||||||||
17 |
Does the DTC reset? | -- | System OK |
