- Before beginning vehicle diagnosis, the following preliminary inspections/tests must be performed:
• | Ensure that the battery cables are clean and tight. |
• | Inspect the easily accessible systems or the visible system components for obvious damage or conditions that could cause the concern. This would include checking to ensure that all connections/connectors are fully seated and secured. |
• | Search for applicable service bulletins. |
- Install a scan tool. Verify that the scan tool powers up.
- Ignition ON, Engine OFF, verify communication with all of the control modules on the vehicle. Refer to
Data Link References for information on the modules you should expect to communicate.
⇒ | If the scan tool does not communicate with one or more of the expected control modules, refer to
Data Link References . |
Important: Open the drivers door to ensure retained accessory power mode (RAP) is inactive during this test. The engine may start during this test. Turn the engine OFF as soon as the crank power mode has been observed.
- Access the Power Mode parameter on the scan tool. Verify the power mode parameter matches all the ignition switch positions. Refer to
Power Mode Description and Operation for information on the power mode states that correspond to each ignition switch position.
⇒ | If the power mode parameter does not match the ignition switch position for all ignition switch positions, refer to
Power Mode Mismatch . |
- Attempt to start the engine. Verify that the engine cranks.
- Attempt to start the engine. Verify the engine starts and idles.
⇒ | If the engine does not start and idle, refer to one of the following: |
Important: Do not clear any DTCs unless instructed to do so by a diagnostic procedure.
Important: If any DTCs are Powertrain related DTCs, select Capture Info in order to store the DTC information with the scan tool. If multiple Powertrain DTCs are stored, diagnose them in the following order:
1. Component
level DTCs; such as sensor DTCs, solenoid DTCs, and relay DTCs.
2. System level DTCs; such as misfire DTCs, EVAP system DTCs, and fuel trim DTCs.
- Advance to the List All DTCs screen on the scan tool selections to obtain DTCs from each of the vehicle modules. Verify there are no DTCs reported from any module.
- If the customer concern is related to inspection/maintenance (I/M) testing, refer to one of the following:
⇒ | If none of the previous tests or inspections addresses the concern, refer to
Symptoms - Vehicle . |