S4 Sedan L5-2226cc 2.22L DOHC Turbo (AAN) (1992)
If NO (for either step):
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Switch ignition OFF (stop engine).
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Wait at least 30 seconds before disconnecting adapter cable from ECM.
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Check wiring for breaks/opens between ECM terminal 6 (terminal 6 of Test Box), and A/C control head terminal C12, using wiring diagram.
If wiring OK:
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Check function of A/C clutch control module - J153.
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Check function of A/C control head - E87.
If A/C control module and A/C control head are OK:
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Replace ECM.
If display position 2 does not change:
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Connect VAG 1598 Test Box, using VAG 1598/5 adapter cable, to ECM. Refer to VAG 1598 Pin Out Box Connecting and Testing. See: Testing
and Inspection/Scan Tool Testing and Procedures/Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting and Testing VAG 1598
Pin Out Box
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Connect US 1115 LED tester or equivalent between terminal 19 (GND) and test box terminal 41 (ECM terminal 41).
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Allow engine to idle.
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Switch ON A/C, selecting lowest temperature/highest blower speed.
^
LED tester must light up.
If NO:
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Switch ignition OFF (stop engine).
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Wait at least 30 seconds before disconnecting adapter cable from ECM.
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Check wiring for breaks/opens between ECM terminal 41 (terminal 41 of Test Box), and A/C control head terminal A2, using wiring diagram.
If wiring OK:
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Check function of A/C
If A/C function is OK:
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Replace ECM.