Ignition System: Testing and Inspection
Misfire Recognition, Checking
Test requirements
- Engine mechanically OK
- There must not be any DTCs stored in DTC memory.
Special tools and equipment
- VAG1551 scan tool (or VAG1552 mobile scan tool) with VAG1551/3B cable
Test sequence
- Connect VAG1551 scan tool (VAG1552). Start engine and select the Engine Control Module (ECM) using address word Disconnecting scan tool and selecting ECM). Refer to " Scan Tool Testing/Scan Tool Connecting and Initial Checks " Testing and Inspection
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read measuring value block" function 08. Press -Q- button to confirm input.
Indicated on display:
Read measuring value block
Enter display group number XXX
- Press 0,1 and 4 for the function "display group number 14", and then press Q to exit from input mode.
Indicated on display: (1 to 4 = display fields)
Read measuring value block 14 ->
1 2 3 4
- Check the total number of misfires in display field 3.
Display Group 14:
- Also check the status of misfire recognition in display field 4.
If specified values are obtained:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06. Press -Q- button to confirm input.
- Switch ignition off.
If specified values are not obtained:
- Change to display group 15 as follows:
- Press button -3- (VAG1551) or up-arrow button (VAG1552).
Indicated on display: (1 to 4 = display fields)
Read measuring value block 15 ->
1 2 3 4
- Check misfires in display fields 1-3.
- Check the status of misfire recognition in display field 4.
Display Group 15:
If specified values are obtained:
- Change to display group 16 as follows:
- Press button -3- (VAG1551) or up-arrow button (VAG1552).
Indicated on display: (1 and 4 = display fields)
Read measuring value block 16 ->
1 4
- Check misfires in display field 1-3.
Display Group 16:
- Check the status of misfire recognition in display field 4.
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06. Press -Q- button to confirm input.
- Switch ignition off.
- Read readiness code. If DTC memory was erased or the Engine Control Module (ECM) was disconnected from the continuous B+ supply, the readiness code must be re-generated. Refer to Monitors, Trip and/or Drive Cycle (Readiness Codes)/Reading Readiness Code. Testing and Inspection Refer to Monitors, Trip and/or Drive Cycle (Readiness Codes)/Generating Readiness Code. Testing and Inspection
Evaluation display group 14, display field 3 - total number of emissions -damaging misfires
Evaluation of display groups 15 and 16, display fields 1 to 3 - total number of emissions -damaging misfires cyl. 1 through cyl. 6
