Passat Sedan L4-1.9L DSL Turbo (AHH) (1998)
Manifold Pressure/Vacuum Sensor: Testing and Inspection
NOTE: The altitude or BAROmetric pressure sensor is located in the Diesel direct injection system ECM. The Manifold Absolute Pressure sensor is a
separate component and is located together with the Intake Air Temperature sensor in a housing on the air intake pipe.
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
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VAG 1551/1552 Scan Tool using VAG 1551/3 adaptor cable
Test sequence
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Connect VAG 1551/1552 Scan Tool. See: Testing and Inspection
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Ensure that ignition is switched ON
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Press 0 and 1 buttons to select Address word 01: "engine electronics"
Display will appear as shown
Rapid data transfer
HELP
Select function xx
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Press 0 and 8 buttons to select Function 08: "Read measuring value block"
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Press Q button to enter input
Display will appear as shown
Rapid measuring value block
HELP
Input display group number xxx
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Press 0, 1 and 0 buttons to select "Display group 10"
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Press Q button to enter input
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Compare display zone 2 (BARO sensor F96) with display zone 3 (Manifold Absolute Pressure sensor G71)
Read measuring value block
10
0 mg/H 1027 mbar 1013 mbar
0.0%
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Specification: both pressures must be the same (tolerance ± 30 mbar)
NOTE: Use the VAG 1397A turbocharger test tool to establish an independent reference value. Set the tool to test range 1 (absolute pressure).
NOTE that an accurately calibrated barometer can also be used.
If value in display zone 3 deviates:
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Press -> button.
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Press 0 and 6 buttons to select Function 06: "End transfer"
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Press Q button to enter input
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Switch OFF ignition.
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Replace Diesel direct injection system ECM J248.
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Display Readiness code. See: Testing and Inspection
If DTC memory has been erased
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Create Readiness code. See: Testing and Inspection
If value in display zone 3 deviates:
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Press -> button.
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Press 0 and 6 buttons to select Function 06: "End transfer"
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Press Q button to enter input
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Start engine
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Press 0 and 8 buttons to select Function 08: "Read measuring value block"
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Press Q button to enter input
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Press 0,1 and 0 buttons to select "Display group 10"
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Press Q button to enter input
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Disconnect Engine speed sensor harness connector. See: Fuel Delivery and Air Induction/Service and Repair
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Observe the value in display field 3
(Manifold Absolute Pressure sensor)
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Value must drop consistently and then equate to the BARO sensor displayed value (display field 21)
Read measuring value block 10
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