Test sequence

• Connect Scan Tool VAG1551 ( VAG1552 ) and select engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idling speed. (Connecting Scan Tool and selecting engine electronics control unit → Scan Tool VAG1551 , connecting  .)

Indicated on display:

• Press buttons 0 and 3 for the function "Output Diagnostic Test Mode".

Indicated on display:

• Confirm input with Q button.

Indicated on display:

• Press the → button.

Indicated on display:

• Press the → button.

Indicated on display:

A/C compressor switch-off is checked.

A/C compressor must stop within 5 seconds (visual check) then start approx. every 5 seconds and then stop.

If the A/C compressor is not switched off:

• Proceed with function 3: Output DTM, until complete.
• Press buttons 0 and 6 for the function "End output" and confirm entry with the Q button.
• Switch off ignition.
• Remove wiper arms and plenum cover: → 92 WINDSHIELD WIPER & WASHER SYSTEM

Fig 1: Identifying Test Box V.A.G 1598/31 Connected To Control Module Wiring Harness

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Connect test box VAG1598/31 to control unit wiring harness.
• Check wiring between test box socket 29 and the A/C system for open circuit using wiring diagram. Wire resistance: Max. 1.5 Ω → Electrical Wiring Diagrams, Troubleshooting and Component Locations
• Check DTC memory and, if necessary, repair any malfunctions and then erase → Diagnostic Trouble Code (DTC) memory, checking and erasing  .
• Read readiness code → Reading readiness code  . If the DTC memory has been erased, the readiness code must be generated again → Readiness code, setting  .

• Connect Scan Tool VAG1551 ( VAG1552 ) and select engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idling speed. (Connecting Scan Tool and selecting engine electronics control unit → Scan Tool VAG1551 , connecting  .)

Indicated on display:

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

Indicated on display:

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

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

• Observe display in display field 3, the A/C must not be switched on.

Specification: 0 X 0 (A/C system signal)

• Switch on A/C system. Do this, depending on A/C system installed by pressing switch "AC" on a manually controlled A/C system or pressing switch "Auto" on an automatic (Climatronic) A/C system.
• Select lowest temperature and highest blower speed. The A/C compressor must run.
• Observe display in display field 3.

Specification: X X 1 (A/C system signal)

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

If the specification is not obtained:

• Remove wiper arms and plenum cover: → 92 WINDSHIELD WIPER & WASHER SYSTEM

Fig 1: Identifying Test Box V.A.G 1598/31 Connected To Control Module Wiring Harness

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Connect test box VAG1598/31 to control unit wiring harness.
• Check wiring between test box socket 34 and A/C system for open circuit using wiring diagram. 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 control unit.
• Check DTC memory and, if necessary, repair any malfunctions and then erase → Diagnostic Trouble Code (DTC) memory, checking and erasing  .
• Read the readiness code → Reading readiness code  . If the DTC memory has been erased, the readiness code must be generated again → Readiness code, setting  .