Test Description

The numbers below refer to the step numbers on the diagnostic table.

2: This step determines if the condition exists.
4: This step determines if the fuel system is contaminated.

DTC P0133

Step	Action	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	IMPORTANT: Inspect the heated oxygen sensor (HO2S) for being secure before proceeding with this DTC. A sensor that is loose could cause this DTC to set. Allow the engine to reach operating temperature. Operate the vehicle within the parameters specified in Conditions for Running the DTC. Observe the diagnostic trouble code (DTC) information with a scan tool. Did DTC P0133 fail this ignition?	Go to Step 4	Go to Step 3
3	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	Go to Step 4	Go to Diagnostic Aids
4	Inspect for an exhaust leak near the HO2S. Refer to Exhaust Leakage in Engine Exhaust. After you inspect the exhaust system, return to this diagnostic. Did you find and correct the condition?	Go to Step 7	Go to Step 5
5	Inspect or test for the following conditions: Inspect that the HO2S is securely installed. Inspect for corrosion on the HO2S terminals. Inspect the terminal tension at the HO2S and at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Inspect the HO2S wiring for damage. Did you find and correct the condition?	Go to Step 7	Go to Step 6
6	IMPORTANT: Determine and correct the cause of the contamination before replacing a sensor. Inspect for the following conditions: Inspect for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (w/o Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (w/Special Tool) . Inspect for the correct RTV sealant. Inspect for engine oil consumption. Refer to Oil Consumption Diagnosis Oil Consumption Diagnosis in Engine Mechanical - 3.6L (LY7). Inspect for engine coolant consumption. Refer to Loss of Coolant in Engine Cooling. Replace the HO2S. Refer to Heated Oxygen Sensor 1 Replacement .Did you complete the replacement?	Go to Step 7	-
7	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	Go to Step 2	Go to Step 8
8	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK