Heater Check

Oxygen Sensor (Before CAT) Heating, Checking

Special tools and equipment
- VAG 1551/VAG 1552 Scan Tool using VAG 1551/3 adapter cable
- VAG 1598/18 Test Box
- Fluke 83 multimeter (or equivalent)
- VW 1594 Adapter kit
- Wiring diagram

Requirement
- Fuse 18 OK

Test sequence
- Connect VAG 1551 (VAG 1552) Scan Tool. Refer to Scan Tool Testing/VAG 1551 Scan Tool. Testing and Inspection
- With engine idling, press buttons -0- and -1- to select "Engine electronics" address word 01.

Display will appear as shown


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select "Read measuring value block" function 08.
- Press -Q- button to enter selection.

Display will appear as shown


Read measuring value block HELP
Input display group number XXX


- Press buttons -1-, -2- and -0- to select "Display group number 120".
- Press -Q- button to enter selection.

Display will appear as shown (1 to 4 = Display fields)


Read measuring value block 120 ->
1 2 3 4


- Check resistance value for Oxygen sensor heating (before cat) (Display field 3).

Display Group 120:

- Press -> button.
- Press buttons -0- and -6- to select "End output" function 06.
- Press -Q- button to enter selection.
- Switch ignition off.


Relevance of figures in 8 digit number block








Continuation







- Disconnect (black) 4-pin connector to Oxygen sensor -1- (before cat) G39.







- Connect multimeter with aux. cables from VW 1594 to measure resistance at terminals 1 + 2 on connector to Oxygen sensor.
- Measure resistance value.
- specification: 0.0 to 24.2 Ohms

If specification not obtained:
- Replace Oxygen sensor (before cat) -G39- If specification obtained:
- Switch multimeter to 20 Volt DC range.







- Connect multimeter between terminals 1 + 2 of ECM connector using jumper wires from VW 1594 adapter kit.
- Measure Voltage supply when display group 120, Display field 4, 1st position from left = 1.
- specification: 11.0 to 14.5 Volts

Measure Voltage supply when display group 120, Display field 4, 1st position from left = alternating 0 and 1.
- specification: between 0.0 and 12.0 Volts and fluctuating

If no Voltage present:







- Connect multimeter between terminal 1 of ECM connector and Ground using jumper wires from VW 1594 adapter kit.
- specification: 11.0 to 14.5 Volts

If again no Voltage present:
- Check wiring between terminal 1 and fuse/relay panel using wiring diagram.

If Voltage present:







- Connect multimeter between terminals 2 and B+ of ECM connector using jumper wires from VW 1594 adapter kit.
- Measure Voltage supply when display group 120, Display field 4, 1st position from left = 1.
- specification: 11.0 to 14.5 Volts

Measure Voltage supply when display group 120, Display field 4, 1st position from left = alternating 0 and 1
- specification: between 0.0 and 12.0 Volts and fluctuating

- Switch ignition off.

If Voltage not present:







- Connect VAG 1598/18 Test Box to ECM wiring harness.







- Check for open circuit between Test Box and 4-pin harness connector using wiring diagram, connecting as follows: terminal 2 + socket 12 wire resistance: 1.5 Ohms maximum

If wiring OK:
- Replace Engine Control Module -J220-.
- Perform Basic setting.
- Create Readiness code again. Refer to Monitors, Trip and/or Drive Cycle (Readiness Codes)/Readiness Code Generating Testing and Inspection

If DTC memory has been erased:
- Read-out Readiness code. Refer to Monitors, Trip and/or Drive Cycle (Readiness Codes)/Readiness Code Checking Testing and Inspection