P0133

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. Then adds the amount of time that the O2S 1 took to complete all the switches. With this information, an average time for all switches can be determined. Whenever the average time to switch is too slow, a DTC P0133 will set.

CONDITIONS FOR SETTING THE DTC

^ DTCs P0106, P0107, P0108, 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 8% and 20%.

^ Evaporative emissions control system is commanded open for greater than 60%.

^ Purge learned memory is greater than approximately 191.

^ The above conditions are present for over 100 seconds.

The average O2S 1 response times are greater than 249mS for rich to lean sweeps or 249mS for lean to rich sweeps.

Or

Ratio of response times is greater than 3.75 or less than 0.4.

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 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.

^ A scan tool can clear the DTCs.

DIAGNOSTIC AIDS

DTC P0133 or slow response is most likely caused by one of the following:

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

^ A leaking fuel injector - A leaking or faulty fuel 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 (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 to 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

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.