With Manufacturer's Scan Tool

Oxygen Sensor (O2S) Heater 1 -Z29- (After Catalytic Converter), Testing

Special tools and equipment






- VAG 1526 A
- VAG 1594 A
- VAG 1598/31

Requirements for test:
- Coolant temperature at least 80 degree C
- Fuse for oxygen sensor heating OK

Test sequence






- Unbolt connector cover -arrows-.






- Unplug 4-pin connector -1- (brown) for oxygen sensor (O2S) behind three way catalytic converter (TWC) -G130-.






- Connect multimeter (resistance measurement range) between contacts 1 and 2.
- Specification: 6.4 to 47.5 ohms (at room temperature)

If the specification is not attained:
- Replace the oxygen sensor (O2S) behind three way catalytic converter (TWC) -G130-.

If the specification is obtained:
- Test voltage supply for oxygen sensor heating.

Testing voltage supply for oxygen sensor heating






- Connect multimeter (voltage measurement range) between contacts 1 (positive) and 2 (Ground).
- Start the engine.
- Specification: approx. battery voltage

NOTE: If required, observe Display Group 041, display zone 4 in the "Read measured value block" function to find out when the engine control module is switching the oxygen sensor heating on and off.

If no voltage is present:






- Connect multimeter (voltage measurement range) as follows:

Connector Measure against
Contact
1 (positive) Vehicle Ground

- Operate starter briefly.
- Specification: approx. battery voltage

If there is still no voltage reading:
- Test for open circuit in wiring connection between fuel pump relay and contact 1 on connector via fuse:

If the voltage supply is OK:






- Connect multimeter (voltage measurement range) as follows:

Connector Measure
Contact against
2 (switched Ground connection Battery positive
for engine control module)

- Start the engine.
- Specification: approx. battery voltage (may fluctuate)
- Switch off ignition.

If no voltage is present:
- Connect test box VAG 1598/31 to wiring harness for engine control module. Do not connect to the engine control module itself. Wiring and Component Testing Using VAG1598/31 Test Box






- Test for open circuits in the following wiring connection:

Connector Test box VAG 1598/31
Contact Socket
2 63

- Correct any open circuits.

If the wiring connection is O.K. but the oxygen sensor heating still has no Ground connection:
- Install a new engine control module.