System 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. With this information, a total for all the switches can be determined. Whenever the number of switches is below a calibrated value, this DTC sets.
Conditions for Setting the DTC
| • | When one or more of the following DTCs are not present P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0300, P0301, P0302, P0303, P0304, P0506, P0507, P1441. |
| • | The number of lean to rich counts is less than 10 or the rich to lean counts is less than 15. |
| • | The engine speed is between 1600 RPM and 2600 RPM. |
| • | The TP angle is between 8.0 % and 20 %. |
| • | The evaporative emissions control system is commanded open for greater than 60 % PWM. |
| • | The purge learn memory is greater than approximately 191. |
Action Taken When the DTC Sets
| • | The Malfunction Indicator Lamp (MIL) illuminates after 2 consecutive ignition cycles in which the diagnostic runs with the fault active. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The Freeze Frame and Failure Records buffers stores this information. |
| • | A history DTC is stored. |
Conditions for Clearing the MIL/DTC
| • | The malfunction indicator lamp (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
DTC P1133 is most likely caused by one of the following conditions:
| • | The fuel pressure - The system will go rich if fuel pressure is too high. The PCM can compensate for some increase; however, if it gets too high, a DTC P0132 will set. Refer to Fuel System Pressure Test . |
| • | A leaking injector - A leaking or faulty 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 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. |
| • | An O2S contamination - Inspect the O2S for a silicone contamination from the fuel or the use of RTV sealant. The sensor may have a white powdery coating. This can result in a high but false voltage signal (rich exhaust indication). |
| • | A PCM ground wire - A loose PCM ground wire at the transmission stud can cause a DTC P1133 to set. O2S 1 voltages stayed between 400 and 500 mV causing not enough switches. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The Powertrain OBD System Check prompts the technician to complete some basic checks and store the Freeze Frame Data and the Failure Records on the scan tool if applicable. This creates an electronic copy of the data taken when the DTC occurs. Refer to this information on the scan tool later.
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Before replacing the PCM, check the terminals for improper mating, broken locks, or physical damage to the wiring harness. Reprogram the replacement PCM. Refer to the latest Techline information for programming procedures.
Step | Action | Value(s) | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | |||||||||||||
2 | Are any component DTCs set? | -- | Go to the Applicable DTC Table | |||||||||||
3 |
Do the parameters show fewer transitions than the specified value? | 15 10 | Go to Diagnostic Aids | |||||||||||
4 | Visually and physically inspect the following items:
Was a problem found in any of the above areas? | -- | ||||||||||||
5 | Check the exhaust manifold for an exhaust leak near the engine. Repair as necessary. Refer to Engine Exhaust. Was an exhaust leak found? | -- | ||||||||||||
6 |
Does the scan tool voltage indicate the voltage within the specified value? | 407 to 509 mV | ||||||||||||
7 |
Does the scan tool voltage indicate the voltage below the specified value? | 200 mV | ||||||||||||
8 |
Notice: Correct the source of the oxygen sensor contamination before replacing
the sensor in order to prevent future contamination. Typical contamination
sources include the following:
Replace the Oxygen Sensor (O2S-1). Refer to Oxygen Sensor Replacement . 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. Refer to Wiring Repairs in Engine Electrical. Is the action complete? | -- | -- | |||||||||||
11 |
Does the O2S-1 voltage measure above the specified value? | 407 mV | ||||||||||||
12 |
Was an O2S-1 low circuit problem found and corrected? | 5 ohms | ||||||||||||
13 |
Was an O2S-1 low circuit problem found and corrected? | 5 ohms | ||||||||||||
14 | Check the O2S-1 low circuit terminal connection at the PCM and replace the terminal if necessary. Did the terminal require replacement? | -- | ||||||||||||
15 |
Did the terminal require replacement? | -- | ||||||||||||
Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||||||||||||
17 |
Does the scan tool indicate that this diagnostic ran and passed? | 90°-95° C | ||||||||||||
18 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | -- | Go to the Applicable DTC Table | System OK |
