Touareg V8-4.2L (BHX) (2004)
Oxygen Sensor: Testing and Inspection
Oxygen Sensors and Sensor Regulation Before Catalytic Converter, Checking
Diagnostic Procedures
Oxygen Sensors and Sensor Regulation before Catalytic Converter, Checking
‹› When servicing terminals in harness connector of oxygen sensors, use only gold-plated terminals.
‹› The oxygen sensors before catalytic converter have a constant regulation and can be differentiated from the oxygen sensor behind catalytic
converter via a 6-pin connector.
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.
‹› Exhaust system must be properly sealed between catalytic converter and cylinder head.
‹› Coolant temperature must be at least 80° C , Diagnostic mode 1: Check measured values; PID 5, Coolant temperature.
‹› Oxygen sensor heaters for oxygen sensors before catalytic converter must be OK, check --> [ Oxygen Sensor Heater before Catalytic Converter,
Checking ] See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and General
Diagnostics/Oxygen Sensor Heater Before Catalytic Converter, Checking.
Function test