Engine Operating Mode, Checking
NOTE: This checks if Engine Control Module (ECM) recognizes the engine operating modes idling, overrun, part throttle, and enrichment.
Special tools and equipment
VAG1551 Scan Tool (ST) or VAG1552 mobile scan tool with VAG1551/3 adapter cable
Test requirements
- Coolant temperature at least 85 °C See display group 004, display field 3.
Test sequence
- Connect VAG1551 (VAG1552) Scan Tool (ST).
- Switch ignition on and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (when doing this engine must be running at idle).
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08 and press -0- button to confirm input.
Indicated on display
Read Measuring Value Block
Input display group number XXX
- Press buttons -0-, -0- and -5- to input display group number 5 (005) and press -Q- button to confirm input.
Indicated on display: (1-4 display fields)
Read Measuring Value Block 5 ->
1 2 3 4
- Check whether control module recognizes operating mode (display field 4):
- Idling: As long as the engine is running at idle speed "Idling" must be displayed.
Display: Idling
- Overrun mode:
- Increase engine speed to above 3000 RPM.
- Close throttle valve abruptly.
Display: Overrun
NOTE: A road test may have to be performed to show "Overrun" in the display.
- Observe valid safety precautions when carrying out road test. Technician Safety Information
- Part throttle:
- Increase engine RPMs evenly. As long as engine is being revved up evenly, "Part throttle" must be displayed.
Display: Part throttle
- Enrichment
- Press accelerator pedal fully to wide open throttle position. Accelerator enrichment must be displayed briefly.
Display: Enrichment
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06 and press -0- button to confirm input.
If the specified values are not obtained:
- Check DTC memory. If necessary, repair any malfunctions and erase DTC memory.
- Check throttle valve control module.
- Display readiness code.
If DTC memory has been erased or the Engine Control Module (ECM) was disconnected from permanent battery (B+) voltage, the readiness code must be generated again.