Functional check

Connect VAG 1551 Scan tool (VAG 1552) and select engine electronics control module with "Address word" 01. Engine must be running at idling speed: (Connecting scan tool and selecting engine electronics control module. See VAG 1551 AND MOTRONIC ENGINE CONTROL MODULE (ECM) -J220-, CONNECTING AND SELECTING ).
Indicated on display:

Fig 1: VAG 1551 Scan Tool Display - Rapid Data Transfer
Courtesy of VOLKSWAGEN OF AMERICA, INC.
Press buttons -0- and -4- for function "Initiate basic setting" and confirm entry with -Q- button. Basic setting
Indicated on display:

Fig 2: VAG 1551 Scan Tool Display - Basic Setting
Courtesy of VOLKSWAGEN OF AMERICA, INC.
Press buttons -0-, -2- and -8- for "Display group number 28" and confirm entry with -Q- button.
Indicated on display: (1 to 4 display zones)

Fig 3: VAG 1551 Scan Tool Display - System In Basic Setting 28
Courtesy of VOLKSWAGEN OF AMERICA, INC.

Only continue with the test when
- The Engine Coolant Temperature (ECT) is above 85 °C - Display zone 3-
Depress brake pedal and hold.
Depress accelerator down to wide open throttle position.
Engine speed will be increased by Engine Control Module (ECM) to approx. 2300 rpm.
Depress brake pedal and accelerator and hold until display in display zone 4 jumps from "Test OFF" to "Test ON".
Depress and hold brake pedal and accelerator until display zone 4 displays specification "Syst. OK."
Release brake and accelerator pedals.
Press --> button.
Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
Switch off ignition.
If "Syst.n.OK." appears in display zone 4:
Check resistance and wiring for knock sensors. See Checking resistance and wiring .