Conditions for Clearing the MIL/DTC

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear DTC Information function.

DTC P0621

Step	Action	Values	Yes	No
Connector End View Reference: Engine Electrical Connector End Views
1	Did you perform the Engine Electrical Diagnostic System Check?	-	Go to Step 2	Go to Diagnostic System Check - Engine Electrical
2	Install a scan tool. Operate the vehicle within the conditions for running the DTC as specified in the supporting text. Using the scan tool, observe the specific DTC Information for DTC P0616 until the test runs. Does the scan tool indicate that DTC P0621 has passed this ignition cycle?	-	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Start the engine. With a scan tool, while observing the Ignition 1 parameter in the engine controls data list, command the Generator L-Terminal Off for 5 seconds and then back on. Does the scan tool indicate a change in voltage each time the Generator L - Terminal is commanded Off and On?	-	Go to Step 6	Go to Step 4
4	Turn OFF the ignition. Disconnect the generator harness connector. Start the engine. Measure the voltage between the generator turn on signal circuit of the generator harness connector and a good ground. Is the voltage within the specified range.	4.5 - 5.5 V	Go to Step 7	Go to Step 5
5	Test the generator turn on signal circuit for a short, high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 8
6	Test the generator battery voltage output circuit for a high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Charging System Test
7	Inspect for poor connections at the harness connector of the generator. Refer to Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Charging System Test
8	Inspect for poor connections at the harness connector of the ECM. Refer to Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 9
9	IMPORTANT: The replacement ECM must be programmed. Replace the ECM. Refer to ENGINE CONTROL MODULE .Did you complete the replacement?	-	Go to Step 10	-
10	Review and record the scan tool Fail Records data. Use the scan tool in order to clear the DTC. Operate the vehicle within the Conditions for Running DTC P0621 as specified in the supporting text. Using the scan tool, observe the Specific DTC Information for DTC P0621 until the test runs. Does the scan tool indicate that DTC P0621 failed?	-	Go to Step 3	System OK