DTC Memory, Checking and Erasing
Requirements:- All fuses OK according to wiring diagram
- Ambient (outside) temperature greater than 10 °C (50 °F)
- Test drive vehicle for at least 5 minutes with A/C switched on
- Engine left running after test drive
- A/C remains on after test drive
- Engine speed (RPM) above idle
NOTE: Do not stop the engine (switch ignition off) after the test drive, or DTC memory will be erased.
Connecting Scan Tool-M.Y. 1997 ON:
- Switch ignition off.
- Connect VAG1551 scan tool with VAG1551/3 adapter to 16-pin Data Link Connector (DLC) in lower left corner of instrument panel, to left of steering wheel. If there is no display, check the voltage supply (B+) to the DLC. Data Link Connector (DLC) Wiring, Checking
Checking:
Indicated on display (Operating modes 1 and 2 are displayed alternately):
V.A.G - ON BOARD DIAGNOSTIC HELP
1 - Rapid data transfer
2 - Blink code output
Press button -1- to select "Rapid data transfer" operating mode 1.
NOTE:
- Press the "HELP" button for additional information.
- Press the -> button to advance the OBD program sequence.
- Press the "PRINT" button to switch on the scan tool printer (indicator lamp in button comes on).
Indicated on display:
Rapid data transfer HELP
Insert address word XX
Press button -0- and -8- to select "A/C Heating Electronics" address word 08.
Indicated on display:
Rapid data transfer Q
08 - A/C Heating Electronics
Press -Q- button to confirm input.
Indicated on display (A/C clutch control module identification and coding):
4A0919579F X Ctl. Air Cond. XXX DXX
Scan tool display Engine
4AO 919 579 F Ctl. Air Cond 6-cyl. 6-cyl. -gasoline
NOTE:
- "DXX" indicates the A/C clutch control module -J153- software version (e.g. D01) and has no meaning for OBD.
- Check control module -J153- applications.
- If the control module code does not correspond to vehicle engine, replace A/C clutch control module
If one of the following messages is displayed:
Rapid data transfer HELP
Control module does not answer
or
Rapid data transfer HELP
K wire not switching to Ground
or
Rapid data transfer HELP
K wire not switching to B+
- Press "HELP" button to print out list of possible causes.
- Check wire connections of DLC. Data Link Connector (DLC) Wiring, Checking
- Check B+ supply to A/C clutch control module -J153- terminals 30 and 75, then check Ground (GND) connection for open circuit using wiring diagram.
- After repairing possible malfunctions, press -0- and -8- buttons to select "A/C Heating Electronics" address word 08.
- Press -Q- button to confirm input.
If display appears as shown:
Error in communication link
- Check Data Link Connector Wiring
- Press -> button.
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press the "HELP" button to print a list of available functions.
- Press buttons -0- and -2- to select the "Check DTC Memory" function 02.
Indicated on display:
Rapid data transfer Q
02 - Check DTC Memory
Press -Q- button to confirm input.
Indicated on display (number of stored DTCs):
X DTC recognized ->
or
No DTC recognized ->
- If the printer is switched on, the stored DTCs (if any) are displayed and printed out one after another.
- Identify and repair malfunctions using DTC table.
- After last malfunction has been displayed and printed:
Press -> button.
Indicated on display:
Rapid data transfer HELP
Select function XX
- Switch ignition off.(DTC memory is erased when ignition is switched off)
- Eliminate/repair any malfunctions.
If the A/C clutch does not engage, even though no malfunction was recognized:
- Check "Read Measuring Value Block," scan tool function 08. Read Measuring Value Block (VAG 1551 Function 08)
- Check output signals from A/C clutch control module using "Output Diagnostic Test Mode" function 03. Output Diagnostic Test Mode (Scan Tool Function 03)