Engine Operating Mode Check
Engine operating mode, checking
NOTE: This checks if Engine Control Module (ECM) recognizes the engine operating modes idling, overrun, part throttle, enrichment, and full throttle.
Special tools and equipment
VAG1551 Scan Tool (ST) or VAG1552 mobile scan tool with VAG1551/3 adapter cable
Test requirements
- Accelerator pedal cable adjustment OK
- Coolant temperature at least 85°C See display group 04, display field 3.
Test sequence
- Connect VAG1551 (VAG1552) Scan Tool (ST), refer to Scan Tool Testing [1][2]Reading and Clearing Diagnostic Trouble Codes
- 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 -Q- 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 abruptly. As long as the engine speed is above 1400 RPM "Overrun" must be displayed.
Display: Overrun
NOTE: Below 1400 RPM idle speed will be recognized.
- Part throttle:
- Increase engine RPMs evenly. As long as engine is being revved up evenly, "Part throttle" must be displayed.
Display: Part throttle
- Full throttle:
- Press accelerator pedal fully to stop (onto throttle valve stop). Full throttle must be displayed briefly.
Display: Full throttle
NOTE: A test drive may have to be performed to display "Full throttle."
Observe the safety precautions when carrying out a road test. Technician Safety Information
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06 and press -Q- button to confirm Input.
If the specified values are not obtained:
- Check DTC memory. If necessary, repair any malfunctions and erase DTC memory.
Reading Diagnostic Trouble Codes
Clearing Diagnostic Trouble Codes
- Check accelerator mechanism for ease of operation.
- Check throttle valve potentiometer. Testing and Inspection
- Display readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
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. Monitors, Trips, Drive Cycles and Readiness Codes