Motronic Engine Control Module (ECM) power supply relay -J271-, checking: Notes

Fig 1: Identifying Special Tools - Motronic Engine Control Module (ECM) Power Supply Relay -J271-, Checking

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Special tools and equipment

VAG1526 A
VAG1594 A
VAG1598/31

NOTE: The Motronic engine control module (ECM) power supply relay -J271- supplies the ignition coils with output stages as well as the engine control module on Pin 121 with power.

Test sequence

Fig 2: Removing Cover In Engine Compartment (Left Side)

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Disconnect cover -1- on left in engine compartment.

Fig 3: Removing Coolant Hoses

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Unbolt coolant expansion tank (arrow).
Disconnect electrical wiring to Engine Coolant Level (ECL) warning switch -F66- on bottom of expansion tank.
Lay coolant expansion tank with connected coolant hoses -1- to -3- aside.

Fig 4: Removing Bolts On Left Cylinder Head & Disconnecting 4-Pin Connectors On Ignition Coils

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Remove bolts (arrows) on left cylinder head.
Disconnect 4-pin connectors -4- to -6- on ignition coils.

NOTE: For further testing, the multimeter is attached to an ignition coil connector.

Fig 5: Identifying Connector Terminals 1 And 4

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Connect multimeter as follows to measure voltage.

Connector Terminal	Measure to
1	Engine ground

Switch ignition on.

Specified value: approx. battery voltage

If specified value is not attained:

Switch ignition off.
Pull off rubber seal of plenum chamber cover.

Fig 6: Identifying Plenum Chamber Cover & Removing Rubber Seal

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Remove plenum chamber cover -1- toward front (arrows).

Fig 7: Removing Securing Clips And Cowl

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Pry off both trim caps -3- with a screwdriver.
Undo hex nuts -4- a few turns.
Release wiper arms -2- from pivot shaft by tilting them slightly.
Remove hex nuts completely and remove wiper arms.

Disconnect retaining clips -1- and remove air cowl grille -5-.

Fig 8: Removing Screws And Cover From E-Box In Plenum Chamber

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Remove cover for electronics box (plenum chamber) (arrows).

Fig 9: Using Screwdriver To Remove Retainer Bar And Engine Control Module (ECM) J623

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Lift off engine control module retaining clip using a screwdriver (arrow) and move control module to side.
If installed, unclip transmission control module retaining clip and place control module on one side.

Fig 10: Removing Motronic Engine Control Module (ECM) Power Supply Relay J271 From E-Box

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Disconnect power supply relay -2-.

Fig 11: Identifying Secondary Air Pump Relay Terminals

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Check for open circuit in following wiring according to wiring diagram:

Relay carrier in electronics box, plenum chamber, position 2 Terminal	Connection of ignition coils Terminal
8	1

Repair open circuit, if necessary.

If no wiring malfunction is detected:

Check voltage supply of Motronic Engine Control Module (ECM) power supply relay -J271-. Refer to Checking power supply .
Check actuation of Motronic Engine Control Module (ECM) power supply relay -J271-. Refer to Checking actuation .