Conditions for Clearing the MIL/DTC

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 P0138

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) 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 reach the normal operating temperature. Operate the engine above 1,200 RPM for 30 seconds and then allow the engine to idle. Observe the heated oxygen sensor (HO2S) 2 voltage parameter with a scan tool. Does the voltage fluctuate rapidly above and below the specified range?	350-550 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) 2. Start the engine. Observe the HO2S 2 voltage parameter with a scan tool. Is the voltage more than the specified value?	500 mV	Go to Step 5	Go to Step 6
5	Test the HO2S 2 signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 11	Go to Step 8
6	Test or inspect for the following conditions: HO2S harness connector for water intrusion. High fuel system pressure- Refer to Fuel System Diagnosis . Rich fuel injectors or fuel injectors that are leaking - Refer to Fuel Injector Balance Test with Special Tool . Exhaust system restrictions. Refer to Symptoms - Engine Exhaust in Engine Exhaust. Fuel saturation of the evaporative emission (EVAP) canister Did you find and correct the condition?	-	Go to Step 11	Go to Step 7
7	Test for shorted terminals and for poor connections at the harness connector of the HO2S 2. 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 11	Go to Step 9
8	Test for shorted terminals and for poor connections at the harness connector of the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition?	-	Go to Step 11	Go to Step 10
9	Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2 . Did you complete the replacement?	-	Go to Step 11	-
10	Replace the ECM. Refer to Engine Control Module (ECM) Replacement . Did you complete the replacement?	-	Go to Step 11	-
11	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 12
12	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List	System OK