Idle Air Control (IAC) Regulation, Initiating Output Diagnostic Test Mode (DTM)

Idle Air Control (IAC) Regulation, Initiating Output Diagnostic Test Mode (DTM)

- Switch ignition off.
- Remove Engine Control Module (ECM) and connect adapter cable of VAG 1598/22 test box to ECM connector. Do not connect ECM to test box.

NOTE: Terminal assignments of harness connectors to ECM:

- Switch ignition on.
- Switch rear window heater off.
- Connect VAG 1551 Scan Tool (ST).
- Press buttons -0- and -8- to insert "AC/Heating Electronics" address word 08 and advance program until "Select function XX" appears on display.
- Switch printer on by pressing PRINT button (indicator lamp in the button comes on).

Indicated on display

Rapid data transfer HELP
Select function XX

- Press buttons -0- and -3- to select "Output Diagnostic Test Mode" function 03.

Indicated on display

Rapid data transfer Q
03 - Output Diagnostic Test Mode

- Press -Q- button to confirm input.

Indicated on display

Function is unknown or
cannot be carried out at the moment

- Press -> button.
- Once again press buttons -0- and -3-.

Indicated on display

Rapid data transfer Q
03 - Output Diagnostic Test Mode

- Press -Q- button to confirm input.

NOTE: If the function "Output Diagnostic Test Mode" is once again entered, the A/C clutch -N25- is no longer actuated, Read Measuring Value Block (Display Group 001).

- To test idling speed regulation function, connect VAG 1527 voltage tester (or equivalent LED type voltage tester) between Ground (GND) and appropriate input (for ECM) on test box.