With Manufacturer's Scan Tool

Oxygen Sensor (O2S) Heating -Z19- For Oxygen Sensor Before Three Way Catalytic Converter (TWC), Checking

Special tools and equipment







- V.A.G 1526 A Multimeter
- V.A.G 1594 A Connector test kit
- V.A.G 1598/31 Test box

Test requirements:
- Coolant temperature at least 80 degree C
- Fuse for Oxygen Sensor (O2S) heating OK.

Test sequence
- Disconnect 6-pin connector (black) -5- to Oxygen Sensor before Three Way Catalytic Converter (TWC) -G39-.







- Connect multimeter between terminals 3 and 4 to measure resistance.
- Specified value at room temperature 2.5 to 10 Ohm

If specified value is not obtained:
- Replace Oxygen Sensor 1 before Three Way Catalytic Converter TWC) -G39-.

If specified value is obtained:
- Check voltage supply for oxygen sensor heating

Checking voltage supply for Oxygen Sensor heating







- Connect multimeter between terminals 3 and 4 to measure voltage.
- Start engine.
- Specified value: approx. battery voltage (B+)

NOTE: Points at which Oxygen Sensor heating is switched on and off by Engine Control Module (ECM) can be observed in "Reading measured value block" function, display group number 041 and display zone 2.

If no voltage is present:







- Connect multimeter as follows to measure voltage.

Connector terminal Measure to
3 Engine ground (GND)

- Operate starter briefly.
- Specified value: approx. battery voltage (B+)

If no voltage is present:
- Check wiring from terminal 3 on the connector via the fuse to fuel pump relay for an open circuit:

If voltage supply is OK:







Connector terminal Measure to
4 (engine control module ground activation) Battery positive (B+)

- Start engine.
- Specified value: approx. battery voltage (B+)

NOTE: Points at which Oxygen Sensor heating is switched on and off by engine control module can be observed in "Reading measured value block" function, display group number 041 and display zone 2.

- Switch ignition off.

If no voltage is present:
- Connect test box V.A.G 1598/31 to wiring harness for engine control module; do not connect directly to Engine Control Module (ECM). Electrical Testing Using VAG1598/31 Test Box







- Check for open circuit in following wiring connections:

Connector terminal Test box V.A.G 1598/31
Socket
4 5

- Repair open circuit, if necessary.

If wiring is OK but there is no ground for the Oxygen Sensor heating:
- Replace Engine Control Module (ECM).