Refer to
Power, Ground, MIL, DLC
schematic.
The Powertrain OBD system check is an organized approach to identifying a problem created by an electronic engine control system malfunction. The Powertrain OBD system check is the starting point for any driveability concern diagnosis, because it directs the service technician to the next logical step in diagnosing the concern. Understanding the table and using it correctly will reduce diagnostic time and prevent the replacement of good parts.
DO NOT perform this check if a driveability concern is not present.
Inspect all related wiring and connections including the connections at the PCM. These may cause an intermittent malfunction. Check terminals for the following:
• | Damaged |
• | Corroded |
• | Pushed out terminals |
Number(s) below refer to the Step number(s) on the Diagnostic Chart:
The MIL should be on steady with the key on engine off. If not, the Malfunction Indicator Lamp (MIL) Inoperative should be used to isolate the malfunction.
This test ensures that the PCM is capable transmitting Class II serial data to the DLC and that the Class II data circuit is not open or shorted. If a DLC problem exists, the Data Link Connector Diagnosis should be used to diagnose the condition.
If the engine will not start, the Engine Cranks but Does Not Run should be used to diagnose the condition.
The scan tool may display DTCs which are diagnosed in Automatic Transaxle Diagnosis. Refer to DTC List for a complete list of DTCs supported by this vehicle application.
A scan tool parameter which is not within the typical range may help to isolate the area which is causing the problem.
Step | Action | Value(s) | Yes | No | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
1 |
IMPORTANT: :
Is the MIL on? | -- | ||||||||||
2 |
Does the scan tool display PCM data? | -- | ||||||||||
3 | Attempt to start the engine. Did the engine start and continue to run? | -- | ||||||||||
4 | Display DTC Info Last Tst Fail. If any DTCs are stored as last test failed, save the freeze frame and fail record information using the Capture Info feature on the scan tool. Are any DTCs indicated as last test failed? | -- | Diagnose the applicable DTCs | |||||||||
5 | Display DTC Fail Records with the scan tool. If any DTC Fail Records are stored, save the freeze frame and fail record information using the Capture Info feature on the scan tool. Are any Fail Records stored? | -- | Go to applicable DTC | |||||||||
6 | Compare PCM data values displayed on the scan tool to the typical engine scan data values. Are the displayed values normal or close to the typical values? | -- | System OK | Refer to indicated Component System Checks |