Test Description

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

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

2: This step determines whether a condition currently exists. If the Lambda value fluctuates near 1.00 and Loop Status is Closed, the HO2S is operating correctly.
4: This step determines if the fuel system is contaminated.

DTC P0133 or P0153

Step	Action	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain 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
2	IMPORTANT: DTC P0133 is for bank 1 sensor 1 - rear and DTC P0153 is for bank 2 sensor 1 - front Inspect the 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 and/or DTC P0153 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 In This Test
4	Did DTC P0133 and DTC P0153 fail this ignition cycle?	Go to Step 7	Go to Step 5
5	Inspect for an exhaust leak near the heated oxygen sensor (HO2S). Refer to Exhaust Leakage . After you inspect the exhaust system, return to this diagnostic. Did you find and correct the condition?	Go to Step 8	Go to Step 6
6	Inspect or test for the following conditions: Inspect for corrosion on the HO2S terminals. Inspect the terminal tension at the HO2S and at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Inspect the HO2S wiring for damage. Did you find and correct the condition?	Go to Step 8	Go to Step 7
7	IMPORTANT: If both DTCs are set, 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 . Inspect for the correct RTV sealant. Inspect for engine oil consumption. Refer to Oil Consumption Diagnosis . Inspect for engine coolant consumption. Refer to Loss of Coolant . Replace the HO2S. Refer to the appropriate procedure: Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 Did you complete the replacement?	Go to Step 8	-
8	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 9
9	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	System OK