Operation CHARM: Car repair manuals for everyone.

With Manufacturer's Scan Tool




Heated Oxygen Sensor (HO2S) and Oxygen Sensor (O2S) Control Before TWC, Checking


NOTE:
- Connector for Heated Oxygen Sensor (HO2S) before Three Way Catalytic Converter (TWC) -G39- (bank 1, sensor 1): 4-pin, black.
- Connector for Heated Oxygen Sensor (HO2S) 2 before Three Way Catalytic Converter (TWC) -G108- (bank 2, sensor 1): 4-pin, black.

Required special tools and test equipment

- VAG 1551 or VAG 1552 Scan Tool (ST) with VAG 1551/3 adapter cable
- VAG 1598/22 test box
- Multimeter US 1119 (Fluke 83 or equivalent)
- VW 1594 connector test kit
- Wiring diagram

Test conditions
- Engine Coolant Temperature (ECT) at least 80 °C (176 °F)

Checking
- Connect VAG 1551 or VAG 1552 scan tool and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with engine running at idle). Connecting VAG 1551 Scan Tool

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-, -3- and -2- to input display group number 32 (032), and press -Q- button to confirm input

Indicated on display (1-4 = display fields)


Read Measuring Value Block 32 ->
1 2 3 4



- Check learning values for Oxygen Sensor (O2S) control before TWC (display fields 1-4):


Display Group 32:






If displayed values are OK (as specified):

- Press -C- button.
- Press buttons -0-, -3- and -3- to input display group number 33 (033), and press -Q- button to confirm input.

Indicated on display (1-4 = display fields)

Read Measuring Value Block 33 ->
1 2 3 4


- Check Oxygen Sensor (O2S) control before TWC (display fields 1-4):


Display Group 33:






Continuation
If the value in either display field 1 or 3 is NOT OK, or if the value does not fluctuate by at least 2 %:
- Road test to condition oxygen sensor(s) (eliminate possible contamination) and repeat test.

If the value in either display field 1 or 3 is still NOT OK, or if it still does not fluctuate by at least 2 %:
- Check Oxygen Sensor (O2S) heater(s).

If the value in either display field 1 or 3 remains constant:
- Check oxygen sensor voltage(s) (display fields 2 and 4).
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.
- Switch ignition off.

Evaluation of display group 32


Display Group 32:






Evaluation of display group 33, display fields 2, 4


Display Group 33:






Checking HO2S reference voltage (banks 1, 2)

- Disconnect 4-pin connector for respective HO2S.







- Connect multimeter US 1119 (Fluke 83 or equivalent) between harness connector terminals 3 and 4 (to ECM), using adapter cables from VW 1594 connector test kit.
- Start engine and measure voltage.
Specified value: 0.40-0.50 volts
- Switch ignition off.

If voltage is NOT OK:
- Check HO2S wiring.
- Bank 1, sensor 1.
- Bank 2, sensor 1.

If voltage is OK:
- Replace respective Heated Oxygen Sensor (HO2S).

Checking HO2S wiring, bank 1, sensor 1

- Disconnect 4-pin connector (black) for HO2S -G39-.
- Connect VAG 1598/22 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 3 to ECM/test box socket 25
- Connector terminal 4 to ECM/test box socket 26
- Specified value: max. 1.5 Ohms
- Check wiring for short circuits between terminals of 4-pin connector, and between connector and ECM/test box.
- Connector terminal 4 to ECM/test box socket 25
- Specified value: Infinity Ohms
- Check wiring for short circuits to wiring harness shielding.
- Connector terminal 4 to ECM/test box socket 14
- Connector terminal 3 to ECM/test box socket 14
- Specified value:

If wiring is OK:
- Replace Motronic ECM -J220-.
- Carry out 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. Audi Drive Cycle/Readiness Code

Checking HO2S wiring, bank 2, sensor 1

- Disconnect 4-pin connector (black) for HO2S -G108-.
- Connect VAG 1598/22 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 3 to ECM/test box socket 39
- Connector terminal 4 to ECM/test box socket 40
- Specified value: max. 1.5 Ohms
- Check wiring for short circuits between terminals of 4-pin connector, and between connector and ECM/test box.
- Connector terminal 4 to ECM/test box socket 39
- Specified value: Infinity Ohms
- Check wiring for short circuits to wiring harness shielding.
- Connector terminal 3 to ECM/test box socket 14
- Connector terminal 4 to ECM/test box socket 14
- Specified value: Infinity Ohm

If wiring is OK:
- Replace Motronic ECM -J220-.
- Carry out 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. Audi Drive Cycle/Readiness Code