Conditions for Clearing the MIL/DTC

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. 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 P0179

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) 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	Operate the engine at idle. Observe the Fuel Comp. Sensor Frequency parameter with a scan tool. Is the frequency more than the specified value?	155 Hz	Go to Step 4	Go to Step 3
3	Operate the engine at idle. Agitate the fuel in the fuel tank by pushing the rear of the vehicle from side to side for 5 seconds. Observe the Fuel Comp. Sensor Frequency parameter with a scan tool for 5 minutes. Did the frequency rise above the specified value?	155 Hz	Go to Step 5	Go to Testing for Intermittent Conditions and Poor Connections
4	Test the fuel composition using the J 44175 Fuel Composition Tester and the Instruction Manual. Record the frequency from the special tool. Compare the tool frequency and the Fuel Comp. Sensor Frequency parameter on the scan tool. Is the different between the two frequencies less than the specified value?	12 Hz	Go to Step 5	Go to Step 6
5	Clean the fuel system. Refer to Fuel System Cleaning . Replace the fuel filter. Refer to Fuel Filter Replacement (5.3L (L59) Engine) . Did you complete the actions?	-	Go to Step 7	-
6	Replace the FCS. Refer to Fuel Composition Sensor Replacement (5.3L (L59) Engine) . 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	System OK