Check Motronic Engine Control Module (ECM) Power Supply Relay -J271- and Activation
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: The Motronic Engine Control Module (ECM) voltage supply relay -J271- supplies voltage to the ignition coils with power output stages and the Engine Control Module (ECM) at pin 121.
Test requirement:
- Ignition switched off.
Test sequence
- Remove engine cover (arrows).
- Disconnect the 4-pin harness connector -1- at one ignition coil -2-.
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 Terminal Measure to
1 Engine Ground (GND)
- Switch ignition on.
- Specified value: approx. battery voltage
- Switch ignition off.
If specified value is not obtained:
- Remove rubber seal for plenum chamber cover.
- Remove plenum chamber cover -1- toward front (arrows).
- Pry off both covers -3- using a screwdriver.
- Loosen hex-nuts -4- by several turns.
- Loosen wiper arm -2- from wiper axle by lightly tilting.
- Remove hex nuts completely and remove wiper arms.
- Disconnect securing clips -1- and remove cowl grill -5-.
- Remove cover for E-box, plenum chamber (arrows).
- Pry off Engine Control Module (ECM) retaining bracket (arrows) using a screwdriver and set control module aside.
- If installed, unclip Transmission Control Module (TCM) retaining bracket and set control module aside.
- Disconnect voltage supply relay -3-.
- Check the following wire connection for open circuit according to wiring diagram:
Relay carrier in E-box, plenum chamber, position 3 Harness connector at ignition coils
Terminal Terminal
8 1
- Specified value: Wire resistance max 1.5 Ohm
- 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 chamber, position 3 Measure to
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 Ohm
Checking activation
- Connect multimeter for voltage measurement as follows.
Relay carrier in E-box, plenum chamber, position 3 Measure to
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 chamber, position 3 Test box Socket
Terminal
4 23
- Specified value: Wire resistance max 1.5 Ohm
- Also check the wire for short circuit to B+ and Ground (GND).
- Specified value: Infinite Ohm (no continuity)
- If necessary, repair wire connection.
If no malfunctions are detected:
- Replace Motronic Engine Control Module (ECM) voltage supply relay -J271-.