Sensor and Sensor Control Check
Sensor and Sensor Control Check
NOTE:
- Raise vehicle to reach oxygen sensor connector.
- Only gold contacts may be used for servicing contacts 3 and 4 in connector for oxygen sensor.
Special tools and equipment
- VAG1551 scan tool or VAG1552 mobile scan tool with VAG1551/3B cable
- VAG1598/31 test box
- VAG1526 hand multimeter or VAG1715 multimeter
- VAG1594 adapter set
- Wiring diagram
Check conditions
- All fuses must be OK.
- The battery voltage must be at least 11.5 V.
- Exhaust system between catalyst and cylinder head must be free of leaks
- Coolant temperature must be at least 80 °C, See display group 04, display zone 3.
Functional check
- Connect VAG1551 scan tool (VAG1552). Start engine and select "Address word" 01 of engine control module. When doing this the engine must be running at idling speed. (Connecting scan tool and selecting engine control module). Refer to "VAG1551 Scan Tool Tools and Equipment
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
Indicated on display:
Read measured value block HELP
Input display group number XXX
- Press keys 0, 3 and 0 for the "Display group number 30" and confirm entry with Q key.
Indicated on display:( 1 to 4 = Display zones)
Read measured value block 30 ->
1 2 3 4
- Check oxygen sensor control status after catalyst (display zone 2):
Specification: 1 1 0
NOTE:
- The first position of the 3 digit number block fluctuates between 0 and 1 (oxygen sensor heating on and off).
- The third position of the 3 digit number block will be set to 1 only at increased exhaust temperature and part load.
Significance of 3 digit number block in display zone 1:
If the specification is not obtained:
- Check the oxygen sensor heating after catalyst. Heater Check
If the specification is obtained:
- Press C key.
- Press keys 0, 3 and 6 for "Display group number 36" and confirm entry with Q key.
Indicated on display: (1 to 4 = Display zones)
Read measured value block 36 ->
1 2 3 4
- Check oxygen sensor voltage after catalyst in display zone 1:
Specification: 0.100 to 0.900 V (can fluctuate slightly)
If the display in display zone 1 remains constant:
- Continue check according to following table.
Possible causes of malfunction if probe control frequency is too slow:
- The slots or holes in probe body are blocked
- The probe vent hole in area of connecting wire is blocked
- The probe has been overheated (glazed)
- The probe has been damaged by leaded fuel
- Check diagnosis result in display zone 2:
Specification: B1-S2 OK
NOTE: It can take a few minutes until display jumps from "Test ON" to "B1-P2 OK".
If "B1-P2" OK is displayed:
- Press -> key.
- Check DTC Memory. Refer to "Displaying and Reading Trouble Codes/With Manufacture Scan Tool/Check DTC Memory (Function 02)" Testing and Inspection
- Carry out a test drive to remove possible residue on oxygen sensor and repeat check.
Observe the valid safety precautions when carrying out a road test Technician Safety Information
If the specifications are again not attained:
- Replace the Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) (G130).
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory,Checking and Erasing DTC Memory. Refer to "Displaying and Reading Trouble Codes/With Manufacture Scan Tool/Check DTC Memory (Function 02)" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again: Refer to "Monitors, Trips and/or Drive Cycle/ Reading Readiness Code" Testing and Inspection
Engine code AWW, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection
Engine code AWP, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection
Checking basic voltage
- Remove protective cover -arrows- and separate 4-pin connector (brown) to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) (G130).
- Connect multimeter with aux. cables from VAG1594 to measure voltage at contacts 3+4 (connector to Motronic control module).
- Start engine and measure the basic voltage.
Specification: 0.40 to 0.50 V
- Switch ignition off.
If the specification is not obtained:
- Check oxygen sensor wiring.
If the specification is obtained:
- Replace Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) (G130).
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory,Checking and Erasing DTC Memory. Refer to "Displaying and Reading Trouble Codes/With Manufacture Scan Tool/Check DTC Memory (Function 02)" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again: Refer to "Monitors, Trips and/or Drive Cycle/ Reading Readiness Code" Testing and Inspection
Engine code AWW, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection
Engine code AWP, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection
Checking oxygen sensor wiring, oxygen sensor 2
- Connect VAG1598/31 test box to control module wiring harness. The engine control module remains disconnected.
- Check wiring between test box and 4-pin connector to Motronic control module for open circuit using wiring diagram.
Contact 3 and socket 68
Contact 4 and socket 69
Wire resistance: max. 1.5 Ohm
- Additionally check wiring at 4-pin connector for short to one another.
Contact 4 and socket 68
Specification: infinity Ohm
If no wiring fault is detected:
- Replace engine control module.