Jetta SportWagen L5-2.5L (CBUA) (2009)
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Using a jumper wire, connect the MAF / IAT sensor (G70 / G42) electrical harness connector terminals 4 to 5.
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Check the value indicated on the scan tool display.
If indication jumps to approx. 140 °C:
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Switch ignition off.
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Replace the MAF / IAT sensor (G70 / G42)
If indication remains at approx. -40 °C or -46 °C:
Checking wiring
If the manufacturers test box is being used, perform the following step.
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Install the test box.
If the manufacturers test box is not being used, perform the following step.
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Remove the Motronic Engine Control Module (ECM) (J623). Refer to --> [ Motronic Engine Control Module, Replacing ] .
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Using a multimeter, check the MAF / IAT sensor (G70 / G42) electrical harness connector terminal 1 to the Motronic Engine Control Module
(ECM) (J623) electrical harness connector T121 terminal 26 for an open circuit or a short to voltage, refer to the wiring diagram.
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Using a multimeter, check the MAF / IAT sensor (G70 / G42) electrical harness connector terminal 3 to the Motronic Engine Control Module
(ECM) (J623) electrical harness connector T121 terminal 27 for an open, high resistance or a short to voltage, refer to the wiring diagram.