With Manufacturer's Scan Tool
Oxygen Sensor (O2S) heater behind TWC, checking
Special tools and equipment
- VAG1551 or VAG1552 Scan Tool (ST) with VAG1551/3 adapter cable
- VAG1598/22 test box
- Multimeter US1119 (Fluke 83 or equivalent)
- VW1594 connector test kit
- Wiring diagram
Checking requirements
- Fuse 29 OK
- Battery voltage: min. 11.5 volts
- Fuel pump relay OK
- Engine coolant temperature at least 85 °C (185 °F) See VAG1551 scan tool function 08, display group 004, display field 3
Checking
- Connect VAG1551 or VAG1552 scan tool and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with engine running at idle), Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG1551/VAG1552 Scan Tool" under "Engine", 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, and press -Q- button to confirm input.
Indicated on display
Read Measuring Value Block HELP
Input display group number XXX
- Press buttons -0-, -4- and -0- to input display group number 40 (040), and press -Q- button to confirm input.
Indicated on display (1-4 = display fields)
Read Measuring Value Block 40 ->
1 2 3 4
- Check HO2S heating resistance after catalytic converter in display field 3.
Display Group 40:
If displayed values are OK (as specified):
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.
- Switch ignition off.
Continuation
If displayed values are NOT OK:
- Switch ignition off.
- Disconnect 4-pin connector for respective Heated Oxygen Sensor (HO2S).
- 4-pin connector (green) for Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130- for bank 1 (arrow).
- 4-pin connector (brown) for Oxygen Sensor (O2S) 2 behind three Way Catalytic Converter (TWC) -G131- for bank 2 (arrow).
- Connect multimeter US1119 (Fluke 83 or equivalent) between O2S connector terminals 1 and 2, using VW1594 connector test kit.
- Measure resistance.
Specified value: 0.0-19.9 Ohms
If resistance is NOT OK:
- Replace respective Oxygen Sensor (O2S).
- Cylinder bank 1 -G130-, item 26, Service and Repair
- Cylinder bank 2 -G131-, item 15, Service and Repair
- Check readiness code. If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If the specification is attained:
- Switch multimeter to 20 VDC measuring range.
- Connect multimeter between harness connector terminals 1 and 2 (to ECM), using VW1594 connector test kit.
- Start engine and run at idle.
- Measure voltage supply and check display in display group 40, display field 4.
If display = Htg.aC.ON:
- Specified value: 11.0-14.5 volts
If display switches between "Htg.aC.ON" and "Htg.aC.OFF":
- Specified value: between 0.0-12.0 volts (oscillating)
- Switch ignition off.
If there is no voltage:
- Connect VAG1598/22 test box to ECM harness connector.
- Check wiring for open circuit between ECM/test box and 4-pin O2S harness connector (to ECM).
- Connector terminal 2 to ECM/test box socket 28
- Specified value: max. 1.5 Ohms
- Check wiring at O2S harness connector terminals 3 and 4 for short circuit to terminals 1 and 2 using wiring diagram.
Specified value: Infinity Ohms
If the specification is attained:
- Check wiring between terminal 1 and fuel pump relay -J17- using appropriate wiring diagram.
- Check readiness code. If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If wiring is OK:
- Replace Motronic ECM -J220-. Service and Repair