Heater Check

Oxygen Sensor Heater For Heated Oxygen Sensor (HO2S) After Three Way Catalytic Converter (TWC), Checking


NOTE:
- Vehicle must be raised before connector to oxygen sensor is accessible.
- When servicing terminals in harness connector of Heated Oxygen Sensor (HO2S), use only gold-plated terminals.

Special tools and equipment
- VAG1551 scan tool (or VAG1552 mobile scan tool) with VAG1551/3B cable
- VAG1598/31 test box
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test requirements







- All fuses must be OK.
- Battery voltage must be at least 11.5 volts.
- Fuel Pump (FP) relay must be OK.

Test sequence
- Connect VAG1551 scan tool (VAG1552). 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 " 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
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 the specified value for oxygen sensor heater in display field 4:

Display Group 41:

If specified values are obtained:
- Press the -> button.
- Press buttons -0- and -6- to select "End Output" function 06. Press -Q- button to confirm input.
- Switch ignition off.

Checking voltage supply







- Disconnect 4-pin harness connector to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130- (arrow).







- Set multimeter for resistance measurement and check resistance of sensor heating between terminals 1 + 2 at connector for oxygen sensor.
Specification: 8.0 to 20.0 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:







- 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. Htng.beh.cat.ON indicated: Specification: 11.0 to 14.5 VHtng.beh.cat.ON/Htng.beh.cat.OFF (alternating) indicated: Specification: oscillating between 0.0 and 12.0 V
- Switch ignition off.

If there is no voltage:







- Connect VAG1598/31 test box 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 specified value is obtained:
- Check wire connection from terminal 1 to Fuel Pump (FP) relay -J17-.

After successful repair:
- Read readiness code. If DTC memory was erased or the Engine Control Module (ECM) was disconnected from the continuous B+ supply, the readiness code must be re-generated. Refer to Monitors, Trip and/or Drive Cycle (Readiness Codes)/Reading Readiness Code. Testing and Inspection Refer to Monitors, Trip and/or Drive Cycle (Readiness Codes)/Generating Readiness Code. Testing and Inspection