With Manufacturer's Scan Tool
Oxygen Sensor (O2S) Heater Before TWC, Checking
NOTE:
- Connector for Oxygen Sensor (O2S) heater -Z19- (bank 1, sensor 1): 4-pin, black.
- Connector for Oxygen Sensor (O2S) 2 heater -Z28- (Bank 2, sensor 1): 4-pin, black.
Required special tools and test 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
Test requirements
- Fuse for Oxygen Sensor (O2S) heater(s) OK
- Engine Coolant Temperature (ECT) at least 80 °C (176 °F)
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). [1][2]Scan Tool Connecting and Initial Checks
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
- Compare display and specified values (display fields 1 and 2):
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
- Disconnect 4-pin connector (black) for respective Heated Oxygen Sensor (HO2S).
- Connect multimeter US1119 (Fluke 83 or equivalent) between HO2S 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 Heated Oxygen Sensor (HO2S).
If resistance is OK:
- Switch multimeter to 20 VDC measuring range.
- Connect multimeter between harness connector terminals 1 and 2 (to ECM), using VW1594 connector test kit.
- Measure voltage supply and check display in display group 40, display field 2.
If display = Htg.bC.ON:
- Specified value: 11.0-14.5 volts
If display switches between "Htg.bC.ON" and "Htg.bC.OFF:"
- Specified value: 0.0-12.0 volts (oscillating)
If there is no voltage:
- Connect multimeter between harness connector terminal 1 (to ECM) and vehicle Ground, using VW1594 connector test kit.
Specified value: 11.0-14.5 volts
If there is still no voltage:
- Check wiring between terminal 1 and relay panel using appropriate wiring diagram.
If there is voltage:
- Connect multimeter between harness connector terminal 2 (to ECM) and Battery Positive Voltage (B+), using VW1594 connector test kit.
- Measure voltage supply and check display in display group 40, display field 2.
If display = Htg.bC.ON:
- Specified value: 11.0-14.5 volts
If display switches between "Htg.bC.ON" and "Htg.bC.OFF:"
- Specified value: 0.0-12.0 volts (oscillating)
- Switch ignition off.
If there is no voltage:
- Connect VAG1598/22 test box to ECM harness connector. Connecting VAG 1598/22 Test Box
- Check wiring for open circuit between ECM/test box and 4-pin HO2S harness connector (to ECM).
- Connector terminal 2 to ECM/test box socket 27
- Specified value: max. 1.5 Ohms
If wiring is OK:
- Replace Motronic ECM -J220-.
- Initiate adaptation of throttle valve control module to ECM.
- Check readiness code. If Diagnostic Trouble Code (DTC) memory has been erased, or ECM was disconnected, generate new readiness code.
Readiness Code Reading
Readiness Code, Generating