P0133

Oxygen Sensor 1 (O2S 1) Circuit:

Circuit Description
The Powertrain Control Module (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
- When one or more of the following DTCs are not set, P0106, P0107, P0108, P011 2, P011 3, P0117, P0118, P0121, P0122, P0123, P0300, P0301, P0302, P0303, P0304, P0506, P0507, Pl171, P1406, P1441.
- The average O2S 1 response times are greater than 249 ms for rich to lean sweeps or 249 ms for lean to rich sweeps.
- The ratio of response times is greater than 3.5 or less than 0.4.
- The engine speed is between 1825 RPM and 2600 RPM.
- The TP angle is between 8% and 20%.
- The Evaporative Emissions Control system is commanded open for greater than 50% PWM.
- The Purge Learned Memory is greater than approximately 191.

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 fault active.
- The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

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.
- DTCs can be cleared by using a scan tool.

NOTE: Whenever the oxygen sensor pigtail wiring, connector or terminal is damaged, the entire oxygen sensor assembly must be replaced. DO NOT attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, the O2S 1 must have a clean air reference. This clean air reference is obtained by way of the oxygen sensor wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degrade the oxygen sensor's performance.

Diagnostic Aids
DTC P0133 or slow response is most likely caused by one of the following:
- 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 P0133 may set.
- Leaking fuel injector - A leaking or faulty fuel 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 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 TP sensor output will cause the system to go rich due to a false indication of the engine accelerating.
- 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.

DTC P0133 - Oxygen Sensor (O2S) Slow Response Sensor 1 (1 Of 2):

DTC P0133 - Oxygen Sensor (O2S) Slow Response Sensor 1 (2 Of 2):

Test Description
Numbers below refer to the Step numbers on the Diagnostic Table.
1. The 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 fault occurred. This information on the scan tool can be referred to later.
16. Before replacing the PCM, check terminals for improper mating, broken locks, or physical damage to the wiring harness. Replacement PCM must be reprogrammed. Refer to the latest Techline information for programming procedures.