Checking Lambda probe and Lambda control after catalytic converter — VW

🧭 Before you start

Fits: VW Passat B5 (3B)

• Special tools named: V.A.G 1551, V.A.G 1552, V.A.G 1594, V.A.G 1598/31
• Renewed: lambda probe, engine control unit

Don't miss

• Bits in display zone 2 are only set to 1 when catalytic converter temperature has exceeded 350°C and a part throttle signal has been detected by engine control unit.

🔧 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, 3 and 0 for "“Display group number 30”" and confirm entry with Q key.
4. Check status of Lambda control after catalytic converter (display zone 2): Specification: 1 1 0 [Note: Bits in display zone 2 are only set to 1 when catalytic converter temperature has exceeded 350°C and a part throttle signal has been detected by engine control unit.]
5. , display group 30 and evaluation

6. Check Lambda probe heating after catalytic converter .
7. Disconnect 4-pin connector (brown) (2) to Lambda probe 2 bank 1 G130 after catalytic converter.
8. Connect multimeter with auxiliary cables from V.A.G 1594 to measure voltage at contacts 3 + 4 (connector to Motronic control unit).
9. Start engine and measure basic voltage. Specification: 0.40...0.50 V
10. Switch off ignition.
11. Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.
12. Check lines between test box and 4-pin connector to Motronic control unit for open circuit referring to current flow diagram.
13. Renew Lambda probe after catalytic converter.
14. Renew engine control unit .
15. Read fault memory, if necessary, repair any faults and then clear fault memory , Reading and clearing fault memory.

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