Diagnostic Mode 08 - Request Control of on-Board System, Test or Component

Diagnostic Mode 08 - Request Control of On-Board System, Test or Component

Diagnostic Mode 08 is used to control the operation of an on-board system, test or component. A Mode 8 service can be used to turn on-board system ON or OFF, or to cycle an on-board system, test or component on or off for a specific period of time. The service can also be used to request system status or to report test results.

Test requirements

• No DTCs stored in the DTC memory.

• Intake Air Temperature (IAT) maximum 60 °C.

• Coolant temperature 80 -110 °C.

• Throttle valve angle 12.0 - 16.0%.

Function test

• If the accelerator pedal is depressed during the test, the test will be aborted.

- Connect the scan tool.

- Start the engine and run at idle for at least 15 minutes.

- Select "Mode 8: Tank Leak Test".

- Select "Test-ID 01: Tank Leak Test".

- Check the specified value of the tank leak test at idle.

- The following will be displayed on the scan tool screen:






- Switch the ignition OFF.

If the specified result is obtained:

System OK.

If the specified result is Not obtained:

- Repeat the tank leak test, switch the ignition off and start the engine again and let run for 15 minutes at idle.

- Switch the ignition OFF.

If the specified result is again Not obtained:

- A leak may be present. Refer to => [ EVAP System, Checking for Leaks ] EVAP System, Checking for Leaks.