Sensor and Control Check
Oxygen Sensor (O2S) and Oxygen Sensor Control After Three Way Catalytic Converter (TWC), Checking
NOTE:
- The vehicle must be raised to gain access to the Oxygen Sensor (O2S) connector.
- Only gold plated terminals may be used to service the terminals in the Oxygen Sensor (O2S) connectors.
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551 Scan tool (or VAG 1552) with VAG 1551/3 adapter cable
NOTE: All functions which could previously be performed with VAG 1551/1552 can also be performed with the VAS 5051.
- VAG 1526 Hand multimeter or VAG 1715 multimeter
- VAG 1594 Adapter set
- VAG 1598/31 test box
- Electrical Wiring Diagrams
Test prerequisites
- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- All electrical accessories, e.g. lights and rear window heating must be switched off.
- If the vehicle is equipped with air conditioning, this must be switched off.
- Selector lever must be in position "P" or "N" on vehicles with an automatic transmission.
- Exhaust system between Three Way Catalytic Converter (TWC) and cylinder head must be free of leaks.
- Engine Coolant Temperature (ECT) must be at least 85 degrees C, See display group 1, display zone 2.
- Three Way Catalytic Converter (TWC) temperature must be at least 380 degrees C, See display group 34, display zone 2.
Functional check
- Connect VAG 1551 Scan tool (or VAG 1552) and select engine electronics control module with the "Address word" 01. When doing this the engine must be running at idle speed: ((VAG 1551 and Motronic Engine Control Module (ECM) -J220-, connecting and selecting). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks".
Testing and Inspection
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- for function "Read measured value (data) block" and confirm entry with -Q- button.
Indicated on display:
Read measured value block
Input display group number XXX
- Press buttons -0-, -3- and -0- for "Display group number 30" and confirm entry with -Q- button.
Indicated on display: (1 to 2 = display zones)
Read measured value block 30 ->
1 2
- Check Oxygen Sensor control status after Three Way Catalytic Converter (TWC) (display zone 2).
Specification: 111
Significance of figures in 3 digit number block. Refer to "Measuring Value Blocks/Measuring Value Blocks/Evaluating Measured Value Blocks".
Testing and Inspection
NOTE: The bits in display zone 1 will not be set to 1 until the Three Way Catalytic Converter (TWC) temperature rises above 380 degrees C (See display groups 34, display zone 2) and a part load signal is recognized by the Motronic Engine Control Module (ECM) -J220-.
If the specification is not obtained:
- Press the -> button.
- Check Oxygen Sensor (O2S) heating after Three Way Catalytic Converter (TWC).
Testing and Inspection
If the specification is obtained:
- Change to display group 36 as follows:
- Press -C- button.
Indicated on display:
Read measured value block
Input display group number XXX
- Press buttons -0-, -3- and -6- for "Display group number 36" and confirm entry with -Q- button.
Indicated on display: (1 to 4 = display zones)
Read measured value block 36 ->
1 2 3 4
- Check Oxygen Sensor (O2S) voltage after Three Way Catalytic Converter (TWC) in display zone 1:
Specification: 0.100 to 0.900 V (must fluctuate slightly)
If the display in display zone 1 fluctuates:
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Switch off ignition.
If the display in display zone 1 remains constantly at a value:
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Switch off ignition.
- Check basic voltage of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
Testing and Inspection
- Check Oxygen Sensor (O2S) wiring of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
Testing and Inspection
If the Oxygen Sensor control in display zone 1 does not fluctuate in the stated range:
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Carry out a road test to remove possible residue on Oxygen Sensor (O2S) and repeat check.
Observe the valid safety precautions when carrying out a road test. Refer to "Fuel Delivery and Air Induction/Service Precautions".
[1][2]Technician Safety Information
If the specifications in display zone 1 are not obtained even after a road test, or the value does not fluctuate:
- Check Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- for aging.
Testing and Inspection
Possible causes of Diagnostic Trouble Code (DTC) if sensor regulation frequency is too slow:
- The slots or holes in sensor body are blocked
- The sensor breather hole in area of connecting cable is blocked
- The sensor has been overheated (glazed)
- The sensor has been damaged by leaded fuel
Check basic voltage of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-
- Remove protective cover -arrows-and disconnect 4-pin connector (black) -1- to Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
- Connect multimeter to measure voltage at terminals 3 and 4 (connector to Motronic control module) using adapter cables from VAG 1594.
- Start engine and measure basic voltage.
Specification: 0.400 to 0.500 V
- Switch off ignition.
If the specification is obtained
- Replace Oxygen Sensor (O2S) 2, Bank 1 after Three Way Catalytic Converter (TWC) (G130), item 18.
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory.Refer to "Displaying and Reading Trouble Codes/With Manufacturer Scan Tool/DTC Memory Checking and Erasing".
Testing and Inspection
- Erase learned values and adapt Motronic Engine Control Module (ECM) -J220- again.
- Read readiness code. If the DTC memory has been erased or the Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive (B+), the readiness code must be generated again. Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Reading Readiness Code".
Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code",
Testing and Inspection
If the specification is not obtained:
- Check Oxygen Sensor (O2S) wiring of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
Testing and Inspection
Checking wiring for Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-
- Remove wiper arms and cowl panel:
- Connect VAG 1598/31 test box to control module wiring harness. The Motronic Engine Control Module (ECM) -J220- remains disconnected.
- Remove protective cover -arrows- and disconnect 4-pin connector (black) -1- to Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
- Check wiring for open circuit between test box and 4-pin connector (to control module) referring to Electrical Wiring Diagrams.
Terminal 3 and socket 68
Terminal 4 and socket 69
Wire resistance: max. 1.5 ohms
- Additionally check wires all for short to one another.
Specification: infinity ohms
If no wiring malfunction is detected:
- Replace Motronic Engine Control Module (ECM) -J220-.
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturer Scan Tool/DTC Memory Checking and Erasing".
Testing and Inspection
- Erase learned values and adapt Motronic Engine Control Module (ECM) -J220- again.
- Read readiness code. If the DTC memory has been erased or the Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive (B+), the readiness code must be generated again. Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Reading Readiness Code".
Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code".
Testing and Inspection