With Generic Scan Tool

Check Motronic Engine Control Module (ECM) Power Supply Relay -J271-and Activation

Special Tools and Equipment







- VAG1526A hand multimeter
- VAG1594A connector test kit
- VAG1598/31 test box

NOTE: Motronic Engine Control Module (ECM) Power Supply Relay -J271- is not installed on all versions.

Test requirement:
- Ignition switched off.

Test sequence







- Remove engine cover (arrows).
- Remove cover -2- above the cylinder head cover, left.







- Disconnect one of the 4-pin harness connectors -4- at ignition coils.

NOTE: For further testing, connect the multimeter to harness connector in place of an ignition coil.







- Connect multimeter for voltage measurement as follows.

Harness connector Measure to
Terminal
1 Engine Ground (GND)

- Switch ignition on.
- Specified value: approx. battery voltage
- Switch ignition off.

If specified value is not obtained:







- Pull off rubber seal of plenum chamber cover in direction of arrow.
- Remove plenum chamber cover -1- toward front.







- Remove cover for E-box, plenum chamber (arrows).







- Pry off Engine Control Module (ECM) retaining bracket (arrow) using a screwdriver and set control module aside.







- Remove voltage supply relay -3-.







- Check the following wire connection for open circuit according to wiring diagram:

Relay carrier in E-box, plenum Harness connector at
chamber, position 3 ignition coils
Terminal Terminal
8 1

- Specified value: Wire resistance max 1.5 Ohms
- If necessary, repair wire connection.

If no malfunctions are found in wires:
- Check voltage supply of Motronic Engine Control Module (ECM) voltage supply relay -J271-.
- Check activation of Motronic Engine Control Module (ECM) voltage supply relay -J271-.

Checking voltage supply







- Connect multimeter for voltage measurement as follows.

Relay carrier in E-box, plenum Measure to
chamber, position 3
Terminal
1 Engine Ground (GND)
2 Engine Ground (GND)

- Specified value: approx. battery voltage

If specified value is not obtained:
- Check wire connections for open circuit according to wiring diagram:
- Specified value: Wire resistance max 1.5 Ohms

Checking activation







- Connect multimeter for voltage measurement as follows.

Relay carrier in E-box, plenum Measure to
chamber, position 3
Terminal
4 B+

- Switch ignition on.
- Specified value: approx. battery voltage
- Switch ignition off.

If specified value is not obtained:
- Connect test box to wiring harness of Engine Control Module (ECM); ECM is not connected. Test Box, Connecting For Wiring Test







- Check the following wire connection for open circuit according to wiring diagram:

Relay carrier in E-box, plenum Test box
chamber, position 3
Terminal Socket
4 23

- Specified value: Wire resistance max 1.5 Ohms
- Also check the wire for short circuit to B+ and Ground (GND).
- Specified value: infinity Ohms (no continuity)
- If necessary, repair wire connection.

If no malfunctions are detected:
- Replace Motronic Engine Control Module (ECM) voltage supply relay -J271-.