Test sequence
WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
- Connect test box V.A.G 1598/31 to wiring harness for ECM; do not connect directly to ECM. See ELECTRICAL TESTING USING VAG1598/31 TEST BOX .
- Switch ignition on.
NOTE:
- The positive voltage supply to the ECM is provided via terminal 3 (terminal 15) and terminal 62 (terminal 30).
- The ground (GND) connection to the ECM is provided via terminal 1 and terminal 2.
- Connect multimeter as follows to measure voltage:
ECM POWER/GROUND CIRCUIT CHECK: SOCKET 1, 2, 62 MEASURE
| Test box V.A.G 1598/31 Socket | Measure to |
|---|---|
| 1 | Battery positive (B+) |
| 2 | Battery positive (B+) |
| 62 | Engine ground (GND) |
- Specified value: approx. battery voltage (B+)
- Connect multimeter as follows to measure voltage:ECM POWER/GROUND CIRCUIT CHECK: SOCKET 3 MEASURE
Test box V.A.G 1598/31 Socket Measure to 3 Engine ground (GND) - Switch ignition on.
- Specified value: approx. battery voltage (B+)
- Check wiring connections.
See appropriate System Wiring Diagram article.
- Connect multimeter as follows to measure voltage:ECM POWER/GROUND CIRCUIT CHECK: SOCKET 121 MEASURE
Test box V.A.G 1598/31 Socket Measure to 121 (1) Engine ground (1) The Motronic Engine Control Module (ECM) Power Supply Relay -J271- carries voltage on terminal 121 of ECM after switching off the ignition for up to 15 minutes. - Switch ignition on.
- Specified value: approx. battery voltage (B+)
- Check wiring connections.
See appropriate System Wiring Diagram article.
- Check Motronic Engine Control Module (ECM) Power Supply Relay -J271-. See MOTRONIC ECM POWER SUPPLY RELAY - J271-, CHECKING .
If the specified values are not obtained:
If specified value is not obtained: