P1133

Diagnostic Chart:

Wiring Diagram:

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

^ DTC P0105, P0106, P0107, P0106, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341 P0404, P0506, P0507, P0601, P0602 not set.

^ Engine speed is between 1600 RPM and 2600 RPM.

^ Throttle Position (TP) angle is between 9% and 20%.

^ Evaporative emissions control system is commanded open for greater than 80% Pulse Width Modulated (PWM) (auto trans).

^ Evaporative emissions control system is commanded open for greater than 40% PWM (manual trans).

^ Purge learned memory is greater than 191.

^ The above conditions are present for at least 100 seconds.

^ The number of rich to lean counts is less than 10 or the lean to rich counts is less than 15.

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/DTC(s) can be cleared by using the scan tool.

DIAGNOSTIC AIDS

DTC P1133 is most likely caused by one of the following:

^ Fuel pressure - The system will go rich if fuel pressure is to high. The PCM can compensate for some increase, however, if it gets too high, a DTC P0172 will be set. Refer to Fuel System Diagnosis.
System Diagnosis - Fuel System

^ Leaking injector - A leaking or malfunctioning injector can cause the system to go rich.

^ 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 Manifold Absolute Pressure (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.

^ 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,

^ TP sensor - An intermittent Throttle Position (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 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

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some 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 is then stored in the scan tool for later reference.

16. Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline information for PCM reprogramming and also refer to the Crankshaft Position (CKP) System Variation Learn Procedure for the Crankshaft Position System Variation Procedure.

18. If no malfunctions have been found at this point and no additional DTCs were set, refer to Diagnostic Aids for additional checks and information.