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 P0641

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	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 3	Go to Intermittent Conditions
3	Turn OFF the ignition. Disconnect the EGR valve. Turn ON the ignition, with the engine OFF. Command the EGR solenoid to 100 percent with a scan tool. Measure the voltage from the 5-volt reference circuit to a good ground with a DMM. Refer toCircuit Testing in Wiring Systems. Is the voltage within the specified range?	4.8-5.2 V	Go to Step 5	Go to Step 4
4	Is the voltage measured in the previous step more than the specified value?	5.2 V	Go to Step 8	Go to Step 6
5	Connect the EGR valve. Disconnect the MAP sensor. Command the EGR solenoid to 100 percent with a scan tool. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified range?	4.8-5.2 V	Go to Intermittent Conditions	Go to Step 11
6	Monitor a DMM while disconnecting all other devices connected to the 5-volt reference circuit, one at a time. Refer to Engine Controls Component Views . If voltage changes when one of the devices are disconnected, replace the component. Refer to the appropriate replacement procedure below: The MAP sensor-Refer to Manifold Absolute Pressure (MAP) Sensor Replacement (L36) or Manifold Absolute Pressure (MAP) Sensor Replacement (L67) . The FTP sensor-Refer to Fuel Tank Pressure Sensor Replacement . The throttle position (TP) sensor. Refer to Throttle Position (TP) Sensor Replacement . Was a component replaced?	-	Go to Step 13	Go to Step 7
7	Turn OFF the ignition. Disconnect the PCM. Test the 5-volt reference circuit for a short to ground or any sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 13	Go to Step 12
8	Monitor the DMM while disconnecting the MAP sensor and FTP sensor, one at a time. Refer to Engine Controls Component Views . If the voltage returns to within the specified value when one of the devices is disconnected, test that sensors signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	4.8-5.2 V	Go to Step 13	Go to Step 9
9	Test the 5-volt reference circuits 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 13	Go to Step 10
10	Test for a short between the EGR 5-volt reference circuit and the EGR solenoid high control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 13	Go to Step 12
11	Replace the EGR valve. Refer to Exhaust Gas Recirculation (EGR) Valve Replacement . Did you complete the replacement?	-	Go to Step 13	-
12	Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement?	-	Go to Step 13	-
13	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 14
14	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