The numbers below refer to the step numbers on the diagnostic table.
This step ensures that the battery, and the vehicle primary power and ground systems are functioning correctly.
Lack of communication may be due to a particular malfunction of a serial data circuit. The link to Data Link References will provide a list of modules and the associated data network no communication diagnostic link.
A Power Mode Master, which is operating in the incorrect power mode based on key position, may cause other symptoms and/or DTCs to set. The link to Power Mode Mismatch will correct the condition before checking for module DTCs or symptoms.
Step | Action | Yes | No | ||||||||||||||
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Perform the following preliminary inspections:
Did you find and correct the condition? | System OK | Go to Step 2 | |||||||||||||||
2 | Install a scan tool. Does the scan tool power up? | Go to Step 3 | Go to Scan Tool Does Not Power Up in Computer/Integrating Systems | ||||||||||||||
Does the scan tool communicate with all of the expected vehicle control modules? | Go to Step 4 | Go to Data Link References in Computer/Integrating Systems | |||||||||||||||
Important:
Does the Power Mode parameter reading on the scan tool match the ignition switch position for all switch positions? | Go to Step 5 | Go to Power Mode Mismatch in Computer/Integrating Systems | |||||||||||||||
5 | Attempt to start the engine. Does the engine crank? | Go to Step 6 | Go to Symptoms - Engine Electrical in Engine Electrical | ||||||||||||||
6 | Attempt to start the engine. Does the engine start and idle? | Go to Step 7 | Go to Engine Cranks But Does Not Run in Engine Controls - 3.5L (LX9) | ||||||||||||||
7 |
Important: Do NOT clear any DTCs unless instructed by a diagnostic procedure.
Advance to the List All DTCs screen on the scan tool. Does the scan tool display any DTCs? | Go to Step 8 | |||||||||||||||
8 | Is the customers concern with inspection/maintenance (I/M) testing? | Go to Inspection/Maintenance (I/M) System Check in Engine Controls - 3.5L (LX9) | Go to Symptoms - Vehicle |