Jetta Wagon L4-1.9L DSL Turbo (ALH) (2003)
also transmitted to the Motronic Engine Control Module (ECM). Confirm G65 circuit using wiring diagram.
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On vehicles where G65 is NOT connected to the ECM, connect green clip from VAG 1767 directly to G65 pin 2 using appropriate VAG 1594
adapter cable - 7 - . Proceed directly to checking.
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Disconnect engine harness electrical connection from Engine Control Module (ECM) - 3 - .
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Locate correct test box VAG 1598A - 4 - and adapter according to pin assignments of ECM - 3 - and connect test box to engine wiring
connector/harness - 2 - .
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Connect black clip from VAG 1767 to Ground (GND) - 5 - .
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Determine applicable G65 signal input pin assignment to ECM using wiring diagram. Example: T121/61
Note:
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As G65 function primarily controls coolant fan and A/C clutch operation, the engine wiring diagrams may indicate the G65 signal connection as
being "Coolant fan control module connection" .
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ECM terminal number assignments correspond with those on test box VAG 1598A .
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Connect green clip from VAG 1767 to the corresponding numbered position on test box VAG 1598A connected to G65 pin - 2 - using appropriate
VAG 1594 adapter cable - 7 - . Example: 61
Checking
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Switch ignition on.
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Press button - arrow - for Duty Cycle measurement (modulation ratio) on ignition tester VAG 1767 (or select same function on equivalent device).
Evaluating results
Note:
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If a malfunction cannot be located, check DTC memory of Engine Control Module (ECM) and the Transmission Control Module (TCM) using
VAG 1551/1552/1552 . When doing so, note that DTCs related to sensor G65 functions may be called-out as "A/C pressure switch -F129-" .