On-Board Diagnostic (OBD II) System Check

ON-BOARD DIAGNOSTIC (OBD II) SYSTEM CHECK

Step	Action	Value(s)	Yes	No
1	Turn the ignition ON with the engine OFF. Observe the Malfunction Indicator Lamp (MIL). Is the MIL on?	-	Go to Step 2.	Go to "NO MALFUNCTION INDICATOR LAMP ".
2	Turn the ignition OFF. Install the scan tool. Turn the ignition ON. Attempt to display the Engine Control Module (ECM) engine data with the scan tool. Does the scan tool display the ECM engine data?	-	Go to Step 3.	Go to Step 7.
3	Using the scan tool output test function, select the MIL dash lamp control and command the MIL off. Observe the MIL. Does the MIL turn OFF?	-	Go to Step 4.	Go to "MALFUNCTION INDICATOR LAMP ON STEADY ".
4	Attempt to start the engine. Does the engine start and continue to run?	-	Go to Step 5.	Go to "ENGINE CRANKS BUT WILL NOT RUN ".
5	Select DISPLAY DTC with the scan tool. Are any Diagnostic Trouble Codes stored?	-	Go to Step 6.	System OK
6	Check the display for DTCs P0107, P0108, P0113, P0118, P0122, P0123, P0172. Are two or more of the following DTCs stored?	-	Go to "MULTIPLE ECM INFORMATION SENSOR DTCS SET "	Go to applicable DTC TABLE .
7	Turn the ignition OFF and disconnect the ECM. Turn the ignition ON with the engine OFF. Check the class 2 data circuit for an open, short to ground, or short to voltage. Also check the Data Link Connector (DLC) ignition feed circuit for an open or short to ground, and check the DLC ground circuits for an open. Is a problem found?	-	Go to Step 8.	Go to Step 9.
8	Repair the open, short to ground, or short to voltage in the class 2 data circuit or the DLC ignition feed circuit. Is the repair complete?	-	System OK	-
9	Attempt to reprogram the ECM. Attempt to display the ECM data with the scan tool. Does the scan tool display ECM engine data?	-	Go to Step 2.	Go to Step 10.
10	Replace the ECM. Is the repair complete?	-	System OK	-