Checking power supply to MAF sensor

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2001 Volkswagen Jetta, 2001 Volkswagen Golf, 2000 Volkswagen Jetta, 2000 Volkswagen Golf, and 1999 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Locating MAF Sensor

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Disconnect 5-pin connector for MAF sensor - arrow -.
Switch ignition on.

Fig 2: 5-Pin Harness Connector & Terminals

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Measure MAF sensor voltage supply between following connector terminals:

Terminal: -G70-	Specification
2 + Ground	Approx. battery voltage
2 + 3	Approx. battery voltage
4 + Ground	Approx. 5.0 V
4 + 3	Approx. 5.0 V

Switch ignition off.

If no voltage is present:

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

Fig 3: Identifying Test Box V.A.G 1598/22 Connected To Control Module Wiring Harness

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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.

Fig 4: 5-Pin Harness Connector & Terminals

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Check wiring between test box and connector for open circuit according to wiring diagram.

	Test box socket no.
Terminal	Through MY 1999	From MY 2000
2	2	1
2	28	2
3	4	49
4	50	30
5	52	68

Wire resistance: max. 1.5 Ω

Check wires for short to one another, to vehicle Ground and to battery positive (B+).

Specification: ∞ Ω

If no wiring malfunction is detected:

Replace engine control module → Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) J248 , replacing .