Oxygen Sensor Heater, Checking
Oxygen Sensor Heater, Checking
NOTE: Use only gold-plated terminals when servicing terminals in harness connector.
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:
- 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 -P-.
- 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.
- Coolant temperature must be at least 80 degrees C, Diagnostic mode 1:Check measured values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measuring Values
- Ignition is switched off.
Test sequence
- Disconnect 6-pin harness connector -1- to Heated Oxygen Sensor (HO2S) -G39-.
- Check resistance for sensor heater at connector to oxygen sensor terminal 3 + 4.
Specified value: Max. 10 Ohms (at room temperature)
If specified value is not obtained:
- Replace Heated Oxygen Sensor (HO2S) -G39-.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If specified value is obtained:
- Check voltage supply and wiring to Engine Control Module (ECM).
Checking voltage supply and wiring to control module
- Connect multimeter to terminal 4 (connector to Engine Control Module -ECM-) + Ground (GND) for voltage measurement.
- Switch ignition on.
Specified value: at least 11.5 V
- Switch ignition off.
If specified value is not obtained:
- Check wire from 6-pin connector terminal 4 to Power Supply (Terminal 30, B+) Relay -J317- according to wiring diagram:
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If specified value is obtained:
- Check Ground (GND) activation of oxygen sensor heater.
Checking Ground (GND) activation of oxygen sensor heater
- 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), connecting test box for wiring test. Test Box, Connecting For Wiring Test
- Check wires between test box and 6-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Terminal 3 + socket 51
Wire resistance: max. 1.5 Ohms
- Check wire for short circuit to B+ and Ground (GND).
Specified value: Infinite Ohms
If no malfunctions are found in wires:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-.