Heater Check
NOTE:
- Raise vehicle to reach oxygen sensor connector.
- Only gold-plated contacts may be used to service contacts in oxygen sensor connector.
Special tools and equipment
- VAG1551 scan tool or VAG1552 mobile scan tool with VAG1551/3B cable
- VAG 1598/31 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.
- Fuel pump relay must be OK
Test sequence
- 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, 4 and 1 for "Display group number 41" and confirm entry with Q key.
Indicated on display: (1 to 4 = Display zones)
Read measured value block 41 ->
1 2 3 4
- Run engine for 2 minutes at idling speed.
- Check oxygen sensor heater status in display zone 2:
Display: Htg.bC.ON, Htg.bC.OFF (alternating)
NOTE: The oxygen sensor heating may be switched on or off depending on the operating mode of the engine, therefore the display in display zone 2 may show "Htg.bC. ON or alternating from Htg.bC.ON to Htg.bC. OFF.
If the display does not indicate as described:
- Press -> key.
- Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
- Switch ignition off.
- Remove protective cover -arrows- and separate 6-pin connector (black) - 1 - to Heated Oxygen Sensor (HO2S) (G39).
- Set multimeter to measure resistance and connect it to contacts 3 + 4 of connector to oxygen sensor. Check oxygen sensor heating for closed circuit.
Specification: 2.5 to 10 Ohm (at room temperature)
If it is determined that oxygen sensor heating has an open circuit:
- Replace the Heated Oxygen Sensor (HO2S)(G39).
- 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
If oxygen sensor heating has continuity:
- Set multimeter to measure voltage and connect to contact 3 (connector to engine control module) and Ground (GND).
- Start engine and run at idling speed.
- Measure voltage supply:
Specification: 11.0 to 14.5V
If the specification is not obtained:
- Check wiring from contact 3 to fuel pump relay (J17) using wiring diagram.
If the specification is obtained:
- Connect multimeter using aux. cables from VAG1594 to measure voltage at contacts 3 and 4 (connector to engine control module).
- Check activation by engine control module while observing display group 41, display zone 2.
Display Htg.bC.ON
Specification: 11.5 to 14.5 V
Display Htg.bC.ON/Htg.bC.OFF (alternating)
Specification: between 0.0 to 12.0 V fluctuating
- Switch ignition off.
If the specification is not obtained:
- Connect VAG1598/31 test box to control module wiring harness. The engine control module remains disconnected.
- Check wiring for open circuit between test box and 6-pin connector using wiring diagram.
Contact 4+socket 5
Wire resistance: max. 1.5 Ohm
If no fault in wire is detected:
- Replace engine control module.