For 1990-2009 cars only
- Before beginning vehicle diagnosis, the following preliminary inspections/tests must be performed:
- 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 Scan Tool Does Not Communicate with Class 2 Device for information on the modules you should expect to communicate.
- Attempt to start the engine. Verify that the engine cranks.
- Attempt to start the engine. Verify the engine starts and idles.
- Use the appropriate scan tool selections to obtain DTCs from each of the vehicle modules. Verify there are no DTCs reported from any module.
- If none of the previous tests or inspections addresses the concern, refer to Symptoms - Vehicle .
| • | Ensure that the battery is fully charged. Refer to Battery Inspection/Test . |
| • | Ensure that the battery cables are clean and tight. |
| • | Inspect for any open fuses. Refer to Power Distribution Schematics and Electrical Center Identification Views . |
| • | Ensure that the grounds are clean, tight, and in the correct location. Refer to Ground Distribution Schematics and Power and Grounding Component Views . |
| • | 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. |
| • | Inspect for aftermarket devices that could affect the operation of the system. Refer to Checking Aftermarket Accessories . |
| • | Search for applicable service bulletins. |
| ⇒ | If the preceding inspections/tests resolve the concern, go to Diagnostic Repair Verification . |
| ⇒ | If the scan tool does not power up, refer to Scan Tool Does Not Power Up . |
| ⇒ | If the scan tool does not communicate with one or more of the expected control modules, refer to Scan Tool Does Not Communicate with Class 2 Device . |
| ⇒ | If the engine does not crank, refer to Symptoms - Engine Electrical . |
| ⇒ | If the engine does not start and idle, refer to Engine Cranks But Does Not Run for the 7.8L (LF8) engine or Engine Cranks But Does Not Run for the 7.8L (LG4) engine. |
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 any DTCs are present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and diagnose any current DTCs in the following order: |
| 6.1. | DTCs that begin with a U. |
| 6.2. | Any of the following: C0550, P0601, P0602, P0603, P0604, P0605, P0606, P062F, or P1621. |
| 6.3. | Any of the following: C0899, C0900, P0562, or P0563. |
| 6.4. | Component level DTCs. |
| 6.5. | System level DTCs. |
| 6.6. | Any remaining DTCs. |
