Oxygen Sensor Heating Before Catalyst Checking
Oxygen sensor heating (Oxygen sensor before Three Way Catalyst), checking
Special tools, testers, measuring instruments and auxiliary items required
- VAG 1551/1552 Scan Tool with VAG 1551/3B adaptor cable
- VAG 1598/22 Test Box
- Fluke 83 Multimeter
- VW 1594 Adaptor kit
- Wiring diagram
Check conditions
- Fuse 29 OK.
- Battery Voltage 11.5 Volts minimum
- Fuel pump relay OK
Test sequence
- Connect VAG 1551/1552 Scan Tool, [1][2][3]Reading and Clearing Diagnostic Trouble Codes
- Start engine and let idle
- Press 0 and 1 buttons to select "Address word" 01 "Engine electronics"
Display will appear as shown
Rapid data transfer HELP
Select function XX
- Press 0 and 8 buttons to select Function 08: "Read measuring value block"
- Press Q button to enter input
Display will appear as shown
Read measuring value block HELP
Input Display group number XXX
- Press buttons 0, 4 and 1 to select "Display group 41"
- Press Q button to enter input
Display will appear as shown (1 to 4 Display zones)
Read measuring value block 41 ->
1 2 3 4
- Check specifications in Display zones 1 and 2 on chart.
If specifications obtained:
- Press -> button.
- Press 0 and 6 buttons to select Function 06: "End data transfer"
- Press Q button to enter input
- Switch OFF ignition.
Continuation
- Disconnect 4-pin harness connector (brown) from Oxygen sensor G39 (before Three Way Catalyst -1-).
- Switch Multimeter to "Resistance measurement" range.
- Connect Multimeter between terminals 1 + 2 of G39 harness connector using jumper wires from VW 1594 adaptor kit
- Measure resistance
- Specification: 0.0 to 19.9 Ohms
If specification not obtained:
- Replace Oxygen sensor G39 (before Three Way Catalyst).
If specification obtained:
- Switch Multimeter to "Voltage measurement" range.
- Connect Multimeter between terminals 1 + 2 of ECM harness connector using jumper wires from VW 1594 adaptor kit
- Start engine and let idle
- Measure Voltage supply
- When Display group 41, Display zone 2 shows
Display, Htg.bC.ON:
Specification: 11.0 to 14.5 Volts
Display, Htg. bC.ON/Htg. bC.OFF (alternating)
Specification: between 0.0 and 12.0 Volts fluctuating
- Switch OFF ignition.
If NO Voltage present:
- Connect VAG 1598/22 Test Box to Control Module harness connector.
- Check wiring for open circuit between Test Box and 4-pin harness connector using Wiring diagram.
- Terminal 2 + socket 27
- Wire resistance: Max. 1.5 Ohms
If specification obtained
- Check wiring between terminal 1 and fuel pump relay J17 using Wiring diagram.
If wiring OK
- Replace Engine Control Module.
- Display Readiness Code, Monitors, Trips, Drive Cycles and Readiness Codes
NOTE:
If DTC memory has been erased or the Engine Control Module was disconnected from its Voltage supply, the Readiness Code must be created again, Monitors, Trips, Drive Cycles and Readiness Codes