With Manufacturer Scan Tool

Oxygen Sensor And Sensor Control After Catalyst, Checking


NOTE:
- Raise vehicle to reach oxygen sensor connector.
- Only gold-plated terminals must be used to repair the terminals 3 and 4 in the connector for the oxygen sensor.


Special tools and equipment
- Scan tool VAG 1551 or vehicle system tester V.A.G 1552 with cable VAG 1551/3B
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
- Adapter set V.A.G 1594
- 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 85 °C, see display group 04, display zone 3

Functional check
- Connect scan tool VAG 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. Engine must be running at idle speed.

Connecting scan tool and selecting Engine Control Module (ECM). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAG1551 Scan Tool" Testing and Inspection

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons 0 and 8 for function "Read measured value 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 status of oxygen sensor control after catalyst (display zone 2).
Specification: 1 1 0


NOTE:
- The first position of the 3 digit number block fluctuates between 0 and 1 (Heated oxygen sensor 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 2







If the specification is not obtained:
- Check Heated oxygen sensor after catalyst.

If the specification is obtained:
- Press C button.
- Press buttons 0, 3 and 6 for "Display group number 36" and confirm entry with Q button.

Indicated on display: (1 to 2 = Display zones)


Read measured value block 36 ->
1 2


- Check oxygen sensor basic 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.

Display Cause
Between 0.400
to 0.490 V Open Circuit
1.100 V Short to positive
0.000 V Short to Ground

Possible causes of malfunction if sensor control frequency is too slow:
- The slots or holes in sensor body are blocked
- The sensor vent hole in area of connecting wire is blocked
- The sensor has been overheated (glazed)
- The sensor has been damaged by leaded fuel

- Check diagnosis result in display zone 2:
Specification: B1-P2 OK


NOTE: It can take a few minutes until display jumps from "Test ON" to "B1-P2 OK".


If "B1-P2 nOk is displayed:
- Press -> button.
- Check DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturers Scan Tool/DTC Memory Checking and Erasing" 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.

If the specifications are again not attained:
- Replace oxygen sensor after catalyst (G130).
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturers Scan Tool/DTC Memory Checking and Erasing" 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/Readiness Code, Displaying" Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Generating" Testing and Inspection

Checking basic voltage







- Remove protective cover -arrows- and separate 4-pin connector (brown) -1- to oxygen sensor after catalyst (G130).







- Connect multimeter with auxiliary cables from V.A.G 1594 to measure voltage at terminals 3 + 4 (connector to Motronic control module).
- Start engine and measure the basic voltage.
Specification: 0.40-0.50 V
- Switch ignition off.

If the specification is not obtained:
- Check oxygen sensor wiring.

If the specification is obtained:
- Replace oxygen sensor after catalyst (G130)
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturers Scan Tool/DTC Memory Checking and Erasing" 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/Readiness Code, Displaying" Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Generating" Testing and Inspection

Checking oxygen sensor wiring, oxygen sensor 2
- Remove inner plenum chamber cover, left:







- Connect test box V.A.G 1598/31 to control module wiring harness. Engine control module is not connected by this action.







- Check wiring for open circuit between test box and 4-pin connector to Motronic control module using wiring diagram.
- Terminal 3 + socket 68
- Terminal 4 + socket 69
Wire resistance: Max. 1.5 Ohms

- Additionally check wiring for short to one another, and for short to battery positive or ground (GND).
Specification: Infinity Ohms

If no wiring problem is detected:
- Replace Engine Control Module (ECM).