The Diagnostic System Check is an organized approach to identifying a condition created by an electronic engine control system malfunction. The Diagnostic System Check must be the starting point for any driveability concern. The Diagnostic System Check directs the service technician to the next logical step in diagnosing the concern. Understanding the table and using the table correctly reduces diagnostic time and prevents the replacement of good parts.
Step | Action | Yes | No | ||||||||||
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1 | Perform the following preliminary inspections:
Did you find and correct the condition? | System OK | Go to Step 2 | ||||||||||
2 |
Does the scan tool turn ON? | Go to Step 3 | Go to Scan Tool Does Not Power Up in Data Link Communications | ||||||||||
3 |
Does the scan tool communicate with all the listed modules? | Go to Step 4 | Go to Data Link References in Data Link Communications | ||||||||||
4 |
Important: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
Refer to the Body Control System Description and Operation in Body Control Systems, for a list of the power mode states that correspond to each ignition switch position. Does the ignition switch parameter reading match the ignition switch position for all switch positions? | Go to Step 5 | Go to Power Mode Mismatch in Body Control System | ||||||||||
5 | Attempt to start the engine. Does the engine crank? | Go to Step 6 | Go to Symptoms - Engine Electrical in Engine Electrical | ||||||||||
6 | Did the engine start and idle? | Go to Step 7 | |||||||||||
7 |
Important: Do NOT clear the DTCs unless instructed by a diagnostic procedure.
For example, sensor DTCs, solenoid DTCs, and relay DTCs. Begin with the lowest number DTC unless the diagnostic table directs you otherwise.
For example, misfire DTCs, EVAP system DTCs, fuel trim DTCs, and system voltage DTCs. Does the scan tool display any DTCs? | Go to Step 8 | Go to Step 10 | ||||||||||
8 | If there are any powertrain DTCs, select Capture Info to store the powertrain DTC information with a scan tool. Did you complete the action? | Go to Step 9 | -- | ||||||||||
9 | Does the scan tool display DTCs which begin with a "U"? | Go to Data Link References in Data Link Communications | |||||||||||
10 | Is the customer's concern with Inspection/Maintenance (I/M) testing? | Go to Step 11 | |||||||||||
11 | Are there any driveability symptoms observed? | System OK |