With Manufacturer's Scan Tool
Heated Oxygen Sensor (HO2S) after Three Way Catalytic Convertor (TWC), checking
Special tools and equipment
- V.A.G1551 Scan Tool (ST) or VAG1552 mobile scan tool with VAG1551/3 adapter cable
- VAG1598/22 test box
- Multimeter (Fluke 83 or equivalent)
- VW1594 adapter set
- Wiring diagram
Test requirements
- Fuse 43 OK
- Battery (B+) voltage at least 11.5 V
- Fuel pump relay OK
Test sequence
- Connect V.A.G1551 (VAG1552) Scan Tool (ST). [1][2]Reading and Clearing Diagnostic Trouble Codes
- Switch ignition on and press buttons -0- and -1- to insert "Engine Electronics" address word 01. Engine must be running at idle when performing this step.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08 and press -Q- button to confirm input.
Indicated on display
Read Measuring Value Block
Input display group number XXX
- Press buttons -0-, -4- and -1- to input display group number 41 (041) and press -Q- button to confirm input.
Indicated on display: (1-4 = display fields)
Read Measuring Value Block 41 ->
1 2 3 4
- Check resistance value for oxygen sensor heater in display field 3.
Display Group 041:
If the specified value is obtained:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06 and press -Q- button to confirm input.
- Turn off ignition.
Continuation
If the specified values are not obtained:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06 and press -Q- button to confirm input.
- Turn off ignition.
- Remove protective cover (arrows) and disconnect 4-pin harness connector (brown) -1- from Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130-.
- Check oxygen sensor heater for continuity at oxygen sensor harness connector terminals 1 and 2.
NOTE: The heating element resistance is approx. 1-5 ohms at room temperature. Even slight increases in room temperature increase the resistance greatly.
If it is determined that the oxygen sensor heater has an open circuit:
- Replace Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130-. Refer item 34 Locations
- Check DTC memory. If necessary, repair any malfunctions and erase DTC memory.
Reading Diagnostic Trouble Codes
Clearing Diagnostic Trouble Codes
- Display readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If DTC memory has been erased, or the Engine Control Module (ECM) was disconnected from permanent battery (B+) voltage, generate the readiness code again. Monitors, Trips, Drive Cycles and Readiness Codes
If oxygen sensor heater has continuity
Checking voltage supply
- Set multimeter to "Voltage measurement" range.
- Connect multimeter using aux. cables from VW1594 to measure voltage at terminals 1 and 2 (harness connector to Engine Control Module (ECM).
- Start engine and run at idle
- Measure voltage supply and observe display group 41, display field 4.
Display: Htg.aC.ON
- Specified value: 11.0-14.5 V
Display: Htg.aC.ON/Htg.aC.OFF (alternating)
- Specified value: Between 0.0-12.0 V fluctuating
- Turn off ignition.
If no voltage is present:
- Remove wiper arms and plenum chamber cover.
- Connect VAG1598/22 test box to control module wiring harness.
- Check wiring between test box and 4-pin harness connector for open circuit according to wiring diagram (terminal -2- + socket 28).
Wire resistance: max. 1.5 ohms
If the specified value is obtained:
- Check wire between 4-pin harness connector terminal -1- and Fuel Pump (FP) relay -J17- for open circuit according to wiring diagram.
Wire resistance: max. 1.5 ohms