Touareg V8-4.2L (BHX) (2004)
Oxygen Sensor: Testing and Inspection
Oxygen Sensor Heater After Catalytic Converter, Checking
Diagnostic Procedures
Oxygen Sensor Heater after Catalytic Converter, Checking
‹› When servicing terminals 3 and 4 in harness connector of oxygen sensors, use only gold-plated terminals.
Special tools, testers and auxiliary items required
‹› Multimeter (VAG1526) or multimeter (VAG1715)
‹› Connector test kit (VAG1594)
‹› Wiring diagram
Test requirements
‹› Fuses in E-box (in plenum chamber, left) must be OK:
‹› Motronic Engine Control Module (ECM) Power Supply Relay (J271) must be OK, check:
‹› Battery voltage must be at least 11.5 volts.
‹› All electrical consumers such as, for example, lights and rear window defroster must be switched off.
‹› Parking brake must be engaged or else daylight driving lights will be switched on.
‹› For vehicles with automatic transmission, selector lever must be in P position.
‹› If vehicle is equipped with an A/C system, it must be switched off.
‹› Ground (GND) connections between engine and chassis must be OK.
Test sequence
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Disconnect 4-pin harness connector to the respective oxygen sensor: