Heater Check

Oxygen Sensor Heater For Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-

Special tools and equipment
- V.A.G 1551 scan tool (or VAG 1552 mobile scan tool) with VAG 1551/3B cable
- VAG 1598/31 adapter cable
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- Wiring diagram

Test requirements







- Fuse no. 34 must be OK.
- Battery voltage must be at least 11.5 volts.
- Fuel Pump (FP) relay must be OK.

Test sequence
- Connect V.A.G 1551 scan tool (VAG 1552). Start engine and select the Engine Control Module (ECM) using address word 01. (connecting scan tool and selecting ECM). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1551 Scan Tool", Testing and Inspection

Indicated on display:


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select "Read measuring value block" function 08. Press -Q- button to confirm input.

Indicated on display:


Read measuring value block HELP
Enter display group number XXX


- Press buttons -0-, -4- and -1- to select "Display group number 41". Press -Q- button to confirm input.

Indicated on display: (1 to 4 - display fields)


Read measuring value block 41 ->
1 2 3 4


- Check resistance of the oxygen sensor heater in display fields 3: Specification: Less than 2 kOhms
- Check the status of the oxygen sensor heater in display field 4: Display: Htng.beh.cat.ON, Htng.beh.cat.OFF (alternating)

If specified values are not obtained:







- Disconnect 4-pin harness connector (brown) to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) - G130- (item no.1).







- Set multimeter for resistance measurement and connect it to terminals 1 + 2 at connector for oxygen sensor. Check oxygen sensor heater for continuity. Specification: 8 to 20 Ohms

If a short circuit is found in the oxygen sensor heater:
- Replace Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.

If oxygen sensor heater has continuity:
- Check voltage supply and wiring

Checking voltage supply and wiring







- Set multimeter for voltage measurement and connect it to terminals 1 + 2 at connector to control module.
- Start engine, and let run at idle.
- Measure voltage supply and observe display group 41, display field 4. Indication Htng.beh.cat.ON: Specification: 11.0 to 14.5 volts. Indication htng.beh.cat.ON/htng.beh.cat.OFF (alternating): Specification: oscillating between 0.0 and 12.0 V

If there is no voltage:
- Connect multimeter to terminal 1 of connector and engine Ground (GND) for voltage measurement.
Specification: 11 to 15 V

If there is no voltage again:
- Check wire connection from terminal 1 to Fuel Pump (FP) relay -J17- according to wiring diagram.

If voltage was approximately same as battery voltage:
- Switch ignition off.







- Connect VAG 1598/31 adapter cable to control module wiring harness. Engine Control Module (ECM) is not connected.







- Check wire between test box and 4-pin connector for open circuit according to wiring diagram. Terminal 2 + socket 63, wire resistance: max: 1.5 Ohms

If no malfunctions are found in wires:
- Replace Engine Control Module (ECM).