Conditions for Clearing the MIL/DTC

WARNING: This page is about a different car, the 2004 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.

DTC P0133

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check-Engine Controls?	-	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	Start the engine. Allow the engine to idle at operating temperature. Refer to Scan Tool Data List . Observe the HO2S 1 parameter with a scan tool. Does the voltage fluctuate rapidly above and below the specified range?	382-525 mV	Go to Step 3	Go to Step 4
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 Intermittent Conditions
4	Turn OFF the ignition. Disconnect the heated oxygen sensor (HO2S) 1 connector. Connect a 3-amp fused jumper wire between the HO2S 1 high signal circuit, on the engine harness side, and a good ground. Turn ON the ignition, with the engine OFF. Observe the HO2S 1 parameter with a scan tool. Is the voltage less than the specified value?	15 mV	Go to Step 5	Go to Step 7
5	Turn OFF the ignition. Remove the jumper wire from the previous step. Probe the HO2S 1 low signal circuit, on the engine harness side, with a test lamp that is connected to B+. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate?	-	Go to Step 6	Go to Step 8
6	Disconnect the appropriate powertrain control module (PCM) harness connector. Measure the resistance between the HO2S 1 low signal circuit and the HO2S low reference circuit, on the engine harness side. Refer to Circuit Testing in Wiring Systems. Is the resistance within the specified range?	0-5 ohm	Go to Step 9	Go to Step 12
7	Test the HO2S 1 high signal circuit for an open or high resistance. Refer to Circuit Testing , Wiring Repairs , and Heated Oxygen Sensor (HO2S) Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 11
8	Test the following circuits for an open or high resistance: HO2S 1 low signal circuit HO2S low reference circuit Refer to Circuit Testing , Wiring Repairs , and Heated Oxygen Sensor (HO2S) Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 11
9	Inspect for the following that may affect the HO2S operation: NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. HO2S contamination NOTE: Refer to Heated Oxygen and Oxygen Sensor Notice in Cautions and Notices. Chafed, burnt, cut, pinched, or otherwise damaged HO2S wiring Exhaust system leaks or restrictions Evaporative emissions (EVAP) system malfunction-Inspect the EVAP control system. Refer to Inspection/Maintenance (I/M) Evaporative Emission (EVAP) System Set Procedure . The fuel pressure-Incorrect fuel pressure can affect HO2S operation. Refer to Fuel System Diagnosis . Did you find and correct the condition?	-	Go to Step 15	Go to Step 10
10	Test for an intermittent and for a poor connection at the harness connector of the HO2S 1. Refer to Testing for Intermittent Conditions and Poor Connections , Connector Repairs and Heated Oxygen Sensor (HO2S) Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 13
11	Test for an intermittent and for a poor connection at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 14
12	Repair the high resistance in the HO2S 1 low signal circuit between the PCM harness connector and the splice. Refer to Wiring Repairs and Heated Oxygen Sensor (HO2S) Wiring Repairs . Did you complete the repair?	-	Go to Step 15	-
13	Replace the HO2S 1. Refer to Heated Oxygen Sensor Replacement - Position 1 . Did you complete the replacement?	-	Go to Step 15	-
14	Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement?	-	Go to Step 15	-
15	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 16
16	Observe the Capture Info with a scan tool. Are there any DTCs that have not diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List	System OK