Work sequence

• Connect Scan Tool V.A.G 1551/1552 → Scan Tool V.A.G 1551 , connecting  .
• Start engine and let idle.
• Press - 0  - and - 1  - buttons to select address word 01: "Engine electronics".

Indicated on display:

Rapid data transfer HELP Select function XX

• Press buttons - 0  - and - 8  - for "Read measured value block" and confirm with - Q  - button.

Indicated on display:

Read measured value block HELP Input display group number XXX

• Press buttons - 0  - , - 0  - and - 2  - for "Display group number 2" and confirm with - Q  - button.

Indicated on display: (1...4 = Display fields)

Read measured value block 2 -> 1 2 3 4

• Switch on air conditioner by pressing A/C button.
• Set lowest temperature and highest blower speed. A/C compressor must run.
• Observe display in display field 3, (3rd position from left)

Read measured value block 2 -> 960 rpm 0.0 % 1 1 1 30.0 ° C

• Specified Value: x x 1 (A/C system signal)

• Press → button.
• Press buttons - 0  - and - 6  - for "End output" and confirm with - Q  - button.
• Switch off ignition.

If specification not obtained:

• Remove wiper arms and cowl panel: →92 WINDSHIELD WIPER & WASHER SYSTEM

• Connect test box V.A.G 1598/22 (through my 1999) or test box V.A.G 1598/31 (from my 2000) to control module wiring harness.
• Check wiring between following test box socket and A/C system for open circuit using wiring diagram.

• Through MY 1999: 48
• From MY 2000: 34
• Wire resistance: Max. 1.5 Ω → Electrical Wiring Diagrams, Troubleshooting and Component Locations

If no malfunction can be found in wiring:

• Check function of A/C Engine Control Module (ECM) J248 signal.
• Check DTC memory, if necessary, repair any malfunctions and erase DTC memory → Diagnostic Trouble Code (DTC) memory, checking and erasing  .
• Display readiness code → Readiness code, displaying  . If DTC memory has been erased, readiness code must be reset → Readiness code, setting  .