Oxygen sensor and oxygen sensor control, checking

Recommended special tools and equipment 

• V.A.G 1526 multimeter or V.A.G 1715 multimeter
• V.A.G 1594 connector test kit
• Wiring diagram

Requirements 

• The respective fuses of Diesel-Direct fuel injection system must be OK:

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

• Battery voltage must be at least 11.5 volts.
• All electrical consumers such as, lights and rear window defroster must be switched off.
• For vehicles with automatic transmission, selector lever must be in position -P- or -N-.
• Parking brake must be engaged.

• 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. Refer to Diagnostic mode 1: Check measured values 

• Oxygen sensor heater for oxygen sensor must be OK, check. Refer to Oxygen sensor heater, checking  .

Checking primary voltage 

• Disconnect 6-pin harness connector -1- to Heated Oxygen Sensor (HO2S) -G39-.

• Connect multimeter to terminals 2 + 6 of connector to Engine Control Module (ECM) for voltage measurement.
• Switch on ignition and measure primary voltage.

Specified value (after approx. 8 seconds): 0.400 to 0.500 Volts

• Switch ignition off.

If specified value is obtained:

• Replace Heated Oxygen Sensor (HO2S) -G39-. Refer to Front exhaust pipe and catalytic converter with attachments  , item 3 .
• Erase DTC memory of Engine Control Module (ECM). Refer to Diagnostic mode 4: Reset/erase diagnostic data 
• Generate readiness code. Refer to Readiness code, generating 

If specified value is not obtained:

• Check wires to Engine Control Module (ECM) according to wiring diagram. Refer to Engine Coolant Temperature (ECT) sensor, checking  .

Check wires to control module 

• Connect test box (1598/42) to Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- wiring harness using adapter cable (V.A.G 1598/39-2). Refer to Test box, connecting for wiring test 

• Check wires between test box and 6-pin connector for open circuit according to wiring diagram.

Terminal 1 + socket 32

Terminal 2 + socket 10

Terminal 5 + socket 54

Terminal 6 + socket 77

Wire resistance: max. 1.5 Ω

• Check wires for short circuit to each other, to vehicle Ground (GND) and to B+.

Specified value: ∞ Ω

If no malfunctions are found in wires:

• Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-. Refer to Engine Control Module (ECM), replacing  .