Checking the diagnostic system (Chevrolet Captiva 1)

Description of the test

The number below refers to the step numbers from the diagnostic table.

1. At this step, the battery and main power supply systems are checked for proper operation and connection to the vehicle's ground

2. The lack of data transmission may be caused by some malfunction of the serial data transmission circuit.

3. This step performs diagnostics on the data link according to the diagnostic trouble codes (DTCs) provided for it, preceding diagnostics according to the DTCs provided for the systems.

4. This step performs diagnostics of the electronic control unit (ECU) in accordance with all the internal fault codes provided for it, preceding diagnostics in accordance with the DTCs provided for other systems.

5. This step diagnoses all instruments according to the voltage supply diagnostic trouble codes, before diagnosing according to the DTCs provided for other systems.

Checking the diagnostic system

Step	Operation	Values	Yes	No
1	Perform the following preliminary checks: Make sure the battery is fully charged. Make sure the battery cables are clean and securely connected. Check for blown fuses. Inspect easily accessible systems or highly visible system components for obvious damage or conditions that could cause the symptom. Make sure ground connections are clean, tight, and properly positioned. Inspect for aftermarket devices that could affect system operation. Check to see if any relevant operating and maintenance bulletins have been issued. Has the problem been detected and corrected?	-	The system is normal	Jump to operations 2
2	Install the diagnostic tool. Does the scanning device turn on?	-	Jump to operations 3	Go to "Scanner does not turn on"
3	Try to start the engine. Does the crankshaft turn?	-	Jump to operations 4	See the item "Crankshaft does not turn" in the section 1E, "Engine electrical equipment"
4	Try to start the engine. Does the engine start and idle?	-	Jump to operations 5	Jump to "The crankshaft turns but the engine does not start"
5	Important: Do not clear any diagnostic trouble codes unless instructed to do so in the diagnostic procedure. To obtain diagnostic trouble codes (DTCs) for each of the controllers, use the corresponding menu items on the scan tool. Does the scan tool display any DTCs?	-	Jump to operations 6	Go to item Signs of malfunction. Engine controls
6	Does the scan tool display any DTCs that begin with "U"?	-	Jump to the appropriate diagnostic trouble code table	-
7	Important: If such DTCs are present, begin troubleshooting for those DTCs and then move on to other DTCs or symptoms. Does the scan tool display any DTCs related to an internal controller failure?	-	Jump to the appropriate diagnostic trouble code table	Jump to operations 8
8	Important: If such DTCs are present, begin troubleshooting for those DTCs and then move on to other DTCs or symptoms. Does the scan tool display any DTCs related to a fault in the battery/ignition voltage supply to the controller?	-	Jump to the appropriate diagnostic trouble code table	Jump to operations 9
9	If several DTCs are stored in the memory, perform diagnostics in the following order. Component level diagnostic trouble codes such as sensor, solenoids and relay DTCs. System-level diagnostic trouble codes such as misfire, evaporative emission (EVAP) and fuel trim DTCs. Diagnostics for other diagnostic trouble codes. Are there any other signs of trouble that concern the customer?	-	Go to item Signs of malfunction. Engine controls	The system is normal