Conditions for Clearing the MIL/DTC

WARNING: This page is about a different car, the 2005 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.

The ECM clears the DTC from ECM history if the vehicle completes 40 warm-up cycles without a non emission diagnostic fault occurring.
The ECM cancels the default action when the ignition is OFF long enough in order to power down the ECM.
A scan tool can clear the DTC.

DTC P0850

Step	Action	Value(s)	Yes	No
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Install a scan tool. Turn ON the ignition with the engine OFF. IMPORTANT: Record the Failure Records before clearing the DTCs. Using the Clear Info function erases the Failure Records. Using the Clear Info function erases stored DTCs in both the ECM and TCM. Record the DTC Failure Records. Clear the DTC. Did you record TCM Failure Records for DTC P1815, P1818, P1820, P1822, P1823, P1825 or P1826?	-	Go to Diagnostic Trouble Code (DTC) List/Type	Go to Step 3
3	Turn ON the ignition with the engine OFF. Select Engine Data 2 on the scan tool. Monitor the PNP Switch display on the scan tool. Shift the transmission to PARK. Does the PNP Switch display Park/Neutral?	-	Go to Step 4	Go to Step 8
4	Shift the transmission from Park to Drive. Does the PNP Switch display "In Gear"?	-	Go to Intermittent Conditions in Engine Controls - 3.6L or Intermittent Conditions in Engine Controls - 4.6L	Go to Step 5
5	Disconnect the automatic transmission inline 20-way connector. Does the PNP Switch display Park/Neutral?	-	Go to Step 6	Go to Step 7
6	Test the PNP Switch signal circuit for a short to ground between the automatic transmission inline 20-way connector and manual shift shaft position switch. Refer to Testing for Short to Ground in Wiring Systems. Did you find the condition?	-	Go to Step 11	Go to Step 12
7	Test the Park/Neutral signal circuit for a short to ground between the automatic transmission inline 20-way connector and the ECM. Refer to Testing for Short to Ground in Wiring Systems. Did you find and correct the condition?	-	Go to Step 14	Go to Step 13
8	Disconnect the automatic transmission inline 20-way connector. Connect the J 45681 jumper harness to the vehicle harness. See Special Tools . Connect a fused jumper from the Park/Neutral signal circuit to ground. Monitor the PNP Switch display. Does the PNP Switch display Park/Neutral?	-	Go to Step 10	Go to Step 9
9	Test the Park/Neutral signal circuit for an open between the automatic transmission inline 20-way connector and the ECM. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 14	Go to Step 13
10	Test the Park/Neutral signal circuit for an open between the automatic transmission inline 20-way connector and the manual shift shaft position switch. Refer to Testing for Continuity in Wiring Systems. Did you find the condition?	-	Go to Step 11	Go to Step 12
11	Replace the transmission internal wiring harness. Refer to Transmission Internal Electrical Harness Replacement . Is the action complete?	-	Go to Step 14	-
12	Replace the manual shaft shift position switch. Refer to Manual Shaft Shift Position Switch Replacement . Is the action complete?	-	Go to Step 14	-
13	Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Is the action complete?	-	Go to Step 14	-
14	Perform the following procedure to verify the repair: Select DTC. Select Clear DTC Information. Turn OFF the ignition for at least 30 seconds. Start the engine. Select Specific DTC. Enter DTC P0850. Has the test run and passed?	-	Go to Step 15	Go to Step 2
15	With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK