Conditions for Clearing the MIL/DTC

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The ECM turns OFF the MIL during the third consecutive trip in which the diagnostic runs and passes.
A scan tool can clear the MIL/DTC.
The ECM clears the DTC from ECM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
The ECM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the ECM.

DTC P0502

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
2	Install a scan tool. Turn ON the ignition with the engine OFF. IMPORTANT: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Record the DTC Freeze Frame and Failure Records. Clear the DTCs. NOTE: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel. Raise the drive wheels. Start and idle the engine. Place the transmission in 1st gear. Monitor Vehicle Speed on the scan tool. With the drive wheels rotating, increase and decrease the throttle position. Does the scan tool indicate Vehicle Speed increasing when wheel speed increases?	-	Refer to Testing for Intermittent Conditions and Poor Connections	Go to Step 3
3	Turn OFF the ignition. Disconnect the VSS. Turn ON the ignition with the engine OFF. Using the DMM, measure the voltage of ignition 1 voltage circuit of the VSS to ground. Does the voltage measure near the specified value?	B+	Go to Step 4	Go to Step 9
4	Measure the voltage from the ignition 1 voltage circuit of the VSS to the VSS ground circuit. Does the voltage measure near the specified value?	B+	Go to Step 5	Go to Step 12
5	Using the J-35616 connector test adapter kit, connect a jumper between the ignition 1 circuit and the VSS. Connect another jumper between the VSS ground circuit and the VSS. Connect the DMM between terminal 1 of the VSS and ground. Turn ON the ignition, with the engine OFF. Select AC volts on the DMM. Place transmission in neutral. Rotate the rear wheels by hand while observing the DMM AC volts. Does the DMM display AC volts above the specified value?	0.15 V	Go to Step 6	Go to Step 16
6	Turn OFF the ignition. Disconnect the ECM. Using the DMM, measure the resistance of the VSS signal circuit between the VSS signal of the ECM and terminal 1 of the VSS. Does the resistance measure less than the specified value?	5 Ω	Go to Step 7	Go to Step 13
7	Using the DMM, measure the resistance between the VSS signal circuit and ground. Is the resistance less than the specified value?	50 kΩ	Go to Step 14	Go to Step 8
8	Using a test lamp connected to the ground, probe the VSS signal circuit. Does the test lamp illuminate?	-	Go to Step 15	Go to Step 18
9	Inspect the BACKUP fuse for an open. Refer to Circuit Protection - Fuses . Replace the fuse if necessary. Was the fuse open?	-	Go to Step 10	Go to Step 11
10	IMPORTANT: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution. Test the ignition 1 voltage circuit of the VSS for a short to ground. Refer to Testing for Short to Ground .Did you find and correct the condition?	-	Go to Step 19	-
11	Test for an open or high resistance in the ignition 1 voltage circuit of the VSS. Refer to Testing for Continuity . Did you find and correct the condition?	-	Go to Step 19	-
12	Repair the open in the VSS ground circuit. Refer to Wiring Repairs . Did you complete the repair?	-	Go to Step 19	-
13	Repair the open in the VSS signal circuit. Refer to Wiring Repairs . Did you complete the repair?	-	Go to Step 19	-
14	Repair the short to ground in the VSS signal circuit. Refer to Wiring Repairs . Did you complete the repair?	-	Go to Step 19	-
15	Repair the short to voltage on the VSS signal circuit. Refer to Wiring Repairs . Did you complete the repair?	-	Go to Step 19	-
16	Remove the VSS sensor. Refer to Vehicle Speed Sensor Replacement . Inspect the VSS and the transmission for the following: Incorrect VSS VSS damage Excessive VSS to rotor gap Incorrect VSS rotor alignment VSS rotor damage Loose VSS Repair any of the above conditions. Did you find and correct the condition?	-	Go to Step 19	Go to Step 17
17	Replace the VSS. Refer to Vehicle Speed Sensor Replacement . Did you complete the repair?	-	Go to Step 19	-
18	Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the repair?	-	Go to Step 19	-
19	In order to verify your repair, perform the following procedure: Select DTC. Select Clear Info. Drive the vehicle. Ensure the vehicle speed is greater than 3 km/h (2 mph) for at least 3 seconds. Select specific DTC. Enter DTC P0502. Has the test run and passed?	-	Go to Step 20	Go to Step 2
20	With a 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	System OK