Output Diagnostic Test Mode (Scan Tool Function 03)
Manually controlled A/C- Check DTC memory, eliminate and repair any malfunctions.
- Keep engine running after checking DTC memory.
- Read measuring value block.
- A/C compressor switch OFF conditions must not be present before preceding
- Switch A/C on
Be sure VAG 1551 scan tool address word 08 "AC/Heating Electronics" is selected.
Indicated on display
Rapid data transfer HELP
Select function XX
NOTE: Press HELP button to print out list of available functions.
- 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.
Either display will appear as shown:
Output diagnostic test mode
A/C compressor engagement
00624 ->
Output check: 0270 (info from literature)
- Perform output DTM "A/C compressor engagement" only if one or more of the following conditions exist:
- Idle Air Control (IAC) precontrol valve too high, idle too high
- Compressor does not engage and code "5" appears in display field 1 of measuring value block
- Engine speed (RPM) fluctuates or irregular idle during A/C operation
- Malfunction "A/C compressor engagement - short circuit to positive"
- Press -> button.
Indicated on display
Output diagnostic test mode ->
A/C magnetic clutch - N25
A/C compressor clutch is switched on and off in 3 second intervals, compressor is driven with clutch engaged.
NOTE: If "Function is unknown or cannot be carried out at the moment" appears in display after A/C clutch switches on, check DTC memory once again. A malfunction exists which is only recognized during output DTM.
If A/C compressor clutch does not engage, or compressor does not rotate when clutch engages:
- Check battery positive voltage (B+) supply to A/C clutch using the wiring diagram.
- With ignition switched off, check compressor by hand for ease of movement.
- Repair A/C clutch.
- Press -> button.
Checking output DTM "A/C compressor engagement"
- Switch ignition OFF and wait 30 seconds.
- Remove Engine Control Module (ECM).
- Connect VAG 1598 test box to connectors A, B, and C of ECM using adaptor cables VAG 1598/11 and/or VAG 1598/12.
- Connect VAG 1527B voltage tester to test box between sockets 45 (GND) and 11 (input for compressor engagement, terminal 87a from A/C clutch control module -J153-).
- Switch engine ON.
Indicated on display 1
V.A.G - On Board Diagnostic HELP
1 - Rapid data transfer
2 - Blink code output
1) Operating modes -1- and -2- appear alternately
- Press button -1- to select "Rapid data transfer" operating mode 1.
Indicated on display
Rapid data transfer HELP
Input address word XX
- Press buttons -0- and -8- to select "A/C heating electronics" address word 08.
Indicated on display
Rapid data transfer Q
08 - AC/Heating Electronics
- Press -Q- button to confirm input.
Control Module identification and coding are displayed, for coding description.
4A0919579 AX ctl. Air Cond. XXX DXX ->
- Press -> button.
Indicated on display
Rapid data transfer HELP
Selection 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.
Either display will appear as shown
Output diagnostic test mode
A/C compressor engagement
If LED does not blink:
00624 ->
Output check: 0270 (info from literature)
- Check wiring between A/C clutch control module -J153- and ECM -J192- harness connector for open or short circuits, according to the wiring diagram, and repair as necessary.
- Press -> button.
Indicated on display
Output diagnostic test mode ->
A/C magnetic clutch - N25
A/C compressor clutch is switched on and off in 3 second intervals, compressor is driven with clutch engaged
- Press -> button.