Oxygen Sensor Heating of Oxygen Sensor (O2S) Heater 1 Behind Three Way Catalytic Converter (TWC) - Z29-, Checking

Oxygen Sensor Heating Of Oxygen Sensor (O2S) Heater 1 Behind Three Way Catalytic Converter (TWC) - Z29-, Checking







Special tools and equipment
- VAG1526A or Fluke 83 Multimeter
- VAG1594A Connector test kit
- VAG1598/31 Test box

Requirements
- Coolant Temperature at least 80 degrees C.
- Fuse for oxygen sensor heating OK

Work sequence







- Remove protective cover -2- (arrows).
- Disconnect 4-pin harness connector (brown) to Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.







- Connect multimeter between terminal 1 and 2 for resistance measurement.
- Specified value at room temperature: 6.4 ... 47.5 Ohms

If specified value is not obtained:
- Replace Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130-.

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

Checking voltage supply for oxygen sensor heating







- Connect multimeter between terminal 1 (B+) and 2 (Ground) for voltage measurement.
- Start engine.
- Specified value: approx. battery voltage

NOTE: When the Engine Control Module (ECM) switches oxygen sensor heating on and off, it may be observed via the function "read measuring value block" in display group number 041 display field 4.

If there is no voltage:







- Connect multimeter for voltage measurement as follows:

Harness connector Measure to
Terminal
1 (B+) Vehicle Ground (GND)

- Operate starter briefly.
- Specified value: approx. battery voltage

If there is no voltage again:
- Check wiring connection from terminal 1 of connector to Fuel Pump (FP) relay via fuse for open circuit

If voltage supply is OK:







- Connect multimeter for voltage measurement as follows:

Harness connector Measure to
Terminal
2 (Ground activation of ECM) Battery positive (+)

- Start engine.
- Specified value: approx. battery voltage, possibly fluctuating
- Switch ignition off.

If there is no voltage:
- Connect VAG1598/31 test box at wiring harness to Engine Control Module (ECM) but do not connect ECM. Scan Tool Testing and Procedures







- Check following wiring connection for open circuit:

Harness connector VAG1598/31 test box
Terminal Socket
2 63

- Repair open circuit in wiring if necessary.

If wiring connection is OK, but there is no Ground (GND) supply for oxygen sensor heating:
- Replace Engine Control Module (ECM).