S4 Sedan L5-2226cc 2.22L DOHC Turbo (AAN) (1992)
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Mass Air Flow Sensor: Testing and Inspection
WARNING!
DO NOT touch the hot wire element in the Mass Air Flow sensor.
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For functional testing of the Mass Air Flow (MAF) sensor, also see On-Board Diagnostics With Scan Tool VAG 1551, "Basic Setting"
function 04. See: Computers and Control Systems/Testing and Inspection/Scan Tool Testing and Procedures/Scan Tool Testing/Basic Setting
(Function 04)
Test condition.
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Circuit breaker S72 - OK.
CAUTION:
Wait 30 seconds after switching OFF the ignition BEFORE disconnecting the Engine Control Module (ECM) harness connector.
Checking ground circuit
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Ignition switched OFF.
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Disconnect harness connector from MAF sensor.
6-Pin Connector
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Connect US 1115 LED tester or equivalent between harness connector terminal 1 and remote positive cable connection.
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LED tester must light up.
If not:
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Locate and repair open in ground circuit, using wiring diagram.
Checking power supply from ECM
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Connect LED tester between MAF sensor terminal 5 and engine Ground (GND).
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Switch ignition ON.
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LED tester must light up.
If not:
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Switch ignition OFF.
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Connect VAG 1598 test box with VAG 1598/5 adapter harness to engine wiring harness. Refer to VAG 1598 Pin Out Box Connecting. See:
Computers and Control Systems/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 LED tester between terminal 19 (GND), and terminal 37 of Test Box.
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Switch ignition ON.
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LED tester must light up.
If Yes:
