P1133

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. You can determine a total for all of the switches with this information. If the number of switches is too low, DTC P1133 will set.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201-P0204, P0300, P0301-P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
^ The Engine Coolant Temperature (ECT) is more than 70°C (158°F).
^ The engine speed is between 1,600-2,450 RPM.
^ The engine is operating in closed loop.
^ The Throttle Position (TP) angle is between 9-18 percent.
^ The evaporative emissions control system is commanded open for more than 36 percent.
^ The purge learned memory is more than approximately 0.78.
^ The fuel level is greater than 10 percent.
^ 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 2, or the lean to rich counts is less than 2.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
DTC P1133 is most likely caused by one of the following conditions:
^ High fuel pressure-The system will go rich if fuel pressure is to high. The PCM can compensate for some increase, however, if the fuel pressure becomes too high, DTC P0172 will be set. Refer to Fuel System Diagnosis. Component Tests and General Diagnostics
^ A leaking injector-A leaking or malfunctioning injector can cause the system to go rich.
^ The Manifold Absolute Pressure (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 Throttle Position (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

Steps 1-9:

Steps 10-18:

The number below refers to the step number on the diagnostic table.
15. The replacement PCM must be programmed and the crankshaft position system variation learn procedure must be performed.