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 Setting the DTC
| • | DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300, P0301, P0302, P0303, P0304, P0506, P0507, P1336, P1404, P1441 are not set. |
| • | The number of rich to lean counts is less than 10. |
| • | The engine speed is between 1600 RPM and 2600 RPM. |
| • | TP angle is between 8 percent and 20 percent. |
| • | Evaporative emissions control system is commanded open for greater than 38 percent PWM. |
| • | Purge learned memory is greater than 128. |
Action Taken When the DTC Sets
| • | The Malfunction Indicator Lamp (MIL) will illuminate. |
| • | 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. |
| • | The coolant fan turns ON. |
| • | The vehicle will operate in an Open Loop operation. |
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 P1133 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 pressure becomes too high, a DTC P0132 will be set. Refer to Fuel System Diagnosis . |
| • | A leaking injector - A leaking or malfunctioning injector can cause the system to go rich. |
| • | A 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 disappears 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. |
| • | The O2S 1 contamination - Inspect the O2S 1 for silicone contamination from fuel or use of 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. |
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 you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data captured when this DTC set. The scan tool stores this data for later reference.
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Reprogram the replacement PCM and perform the crankshaft position system variation learning procedure. Refer to the latest Techline procedures for PCM reprogramming and the Powertrain Control Module (PCM) for the crankshaft position system variation learning procedure.
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If no malfunctions are present at this point and no additional DTCs were set, refer to 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 | Are any component DTCs set? | -- | Go to Component DTC table | |||||||||||
3 |
Do the parameters show fewer transitions than the specified values? | 30-40 (auto) 10-15 (man) | ||||||||||||
4 | Visually/physically inspect the following items:
Was a problem present in any of the above areas? | -- | ||||||||||||
5 | Check the exhaust manifold for an exhaust leak near the engine and repair the leak as necessary. Was a repair necessary? | -- | ||||||||||||
6 |
Does the scan tool voltage indicate the O2S 1 voltage within the specified value? | 407-509 mV | ||||||||||||
7 | Jumper the O2S 1 high circuit (PCM side) signal circuit to ground. Does the scan tool voltage indicate that the O2S 1 voltage is within the specified value? | 200 mV | ||||||||||||
8 | Replace the Oxygen Sensor (O2S 1). Notice: Determine and correct the cause of the contamination in order to prevent damage to the replacement sensors.
Is the action complete? | -- | -- | |||||||||||
9 | Repair the condition as necessary. Is the action complete? | -- | -- | |||||||||||
10 | Repair the O2S 1 signal circuit for a short to ground. Is the action complete? | -- | -- | |||||||||||
11 |
Does the O2S 1 voltage measure above the specified value? | 407 mV | ||||||||||||
12 |
Was an O2S 1 signal circuit problem found and corrected? | 5ohms | ||||||||||||
13 |
Was an O2S 1 signal circuit problem found and corrected? | 5ohms | ||||||||||||
14 | Check the O2S 1 low circuit terminal connection at the PCM and replace the terminal. Did the terminal require replacement? | -- | ||||||||||||
15 | Check the O2S 1 signal circuit terminal connection at the PCM and replace the terminal. Did the terminal require replacement? | -- | ||||||||||||
Replace the PCM. Is the action complete? | -- | -- | ||||||||||||
17 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||||||||||||
Check to see if any additional DTCs are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to applicable DTC table | System OK Refer to Diagnostic Aids |
