Checking control unit voltage supply: VW Passat B5 2.3 (AZX)

🧭 Before you start

Fits: VW Passat B5 (3B)

• Special tools named: V.A.G 1551, V.A.G 1552, V.A.G 1598/31, V.A.G 1594

🔧 Engine codes this applies to

📋 Procedure

1. Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "“Address word”" 01 of engine control unit. (Connect fault reader and select engine control unit )
2. Press keys 0 and 8 for function "“Read measured value block”" and confirm entry with Q key.
3. Press keys 0, 0 and 4 for "“Display group number 4”" and confirm entry with Q key.
4. Read off figure displayed in display zone 2. Specification: At least 11.5 V
5. , display group 4 and evaluation

6. Press → button.
7. Press keys 0 and 6 for function "“End data transfer”" and confirm entry with Q key.
8. Switch off ignition.
9. Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.
10. Measure supply voltage between test box sockets 1+62 using multimeter and test leads from V.A.G 1594: Specification: At least 11.5 V
11. Check wiring connections to relay plate referring to current flow diagram: .
12. Measure supply voltage between test box sockets 2+3 using multimeter and test leads from V.A.G 1594: Specification: At least 11.5 V
13. Switch on ignition. Specification: at least 11.5 V
14. Check wiring connections to relay plate referring to current flow diagram: .
15. Read fault memory, if necessary, repair any faults and then clear fault memory , Reading and clearing fault memory.

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