P0133
P0133 O2 Bank 1 Sensor 1 Slow Response
Circuit Description
The powertrain control module (PCM)/engine control module (ECM) continuously monitors the Oxygen Sensor (O2S) activity for 100 seconds. During the monitor period, the PCM/ECM counts the number of times that the O2S switches from rich to lean and from lean to rich and adds the amount of time it took to complete all switches. With this information, an average time for all switches can be determined. If the average time to switch is too slow, a Diagnostic Trouble Code (DTC) P0133 will set.
If the O2S pigtail wiring, connector or terminal are damaged, the entire O2S assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have a clean air reference provided to it. This clean air reference is obtained by way of the O2S wire(s). Any attempt to repair the wires, connector or terminals could result in the obstruction of the air reference and degrade O2S performance.
Conditions for Setting the DTC
- DTCs P0106, P0107, P0108, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0134, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0336, P0337, P0351, P0352, P0402, P0404, P0405, P0406, P0506, P0507, P1404, P1441 and P1627 are not set.
- Closed loop stoichiometry.
- Engine Coolant Temperature (ECT) is greater than 162 °F (72 °C).
- Engine run time is greater than 120 seconds.
- Purge Duty Cycle (D.C.) is greater than 0%.
- rpm is between 1600 and 4000.
- Airflow is between 9 and 40 g/sec.
Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The PCM/ECM 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.
- DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
DTC P0133 or slow response is most likely caused by one of the following items:
- Fuel pressure - The system will go rich if fuel pressure is too high. The PCM/ECM can compensate for some increase; however, if it gets too high, a DTC P0133 may set. Refer to "Fuel System Diagnosis".
- Leaking injector - A leaking or malfunctioning injector can cause the system to go rich.
- Manifold Absolute Pressure (MAP) sensor - An output that causes the PCM/ECM 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/ECM 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 pressure regulator.
- Throttle Position (TP) sensor - An intermittent TP sensor output can cause the system to go rich due to a false indication of the engine accelerating.
- O2S contamination - Inspect O2S for silicone contamination from fuel or use of improper room temperature vulcanizing (RTV) sealant. The sensor may have a white powdery coating and result in a high but false voltage signal (rich exhaust indication). The PCM/ECM will then reduce the amount of fuel delivered to the engine causing a severe surge or drive- ability problem.
Step 1 - 6:
Step 7 - 17:
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. The On-Board Diagnostic (OBD II) 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 on the scan tool for later reference.
14. The replacement PCM/ECM must be reprogrammed. Refer to the latest Techline procedure for PCM/ECM reprogramming.
17. If no malfunctions have been found at this point and no additional DTCs were set, refer to "Diagnostic Aids" for additional checks and information.