Oxygen Sensor and Oxygen Sensor Control Behind Catalytic Converter, Checking

Oxygen Sensor And Oxygen Sensor Control Behind Catalytic Converter, Checking

NOTE:
- Vehicle must be raised before connector for oxygen sensor is accessible.
- When servicing terminals 3 and 4 in harness connector of Heated Oxygen Sensor (HO2S), use only gold-plated terminals.

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 Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- 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.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- For vehicles with automatic transmission, selector lever must be in position -P- or -N-
- 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 degrees C. Diagnostic mode 1: Check measured values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measured Values
- Oxygen sensor heater for oxygen sensor behind catalytic converter must be OK, check.

Function test
- Select following output of oxygen sensor signals and check whether specified values are being reached. Diagnostic mode 5: Check output of oxygen sensor signals. Diagnostic Mode 5: Check Output of Oxygen Sensor Signals

If specified values are obtained:
- End diagnosis and switch ignition off.

If specified values are not obtained:
- End diagnosis and let engine continue to run at idle.
- Check primary voltage.

Checking primary voltage







- Remove protective cover (arrows) and disconnect 4-pin harness connector (brown) -1- to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130-.







- Connect multimeter for voltage measurement to terminals 3 + 4 of connector to Engine Control Module (ECM) and measure primary voltage.

Specified value: 0.400 to 0.500 Volts

- Switch ignition off.

If specified value is not obtained:
- Test oxygen sensor wires.

If specified value is obtained:
- Replace Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-.
- 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

Checking oxygen sensor wires
- Connect test box to control module wiring harness. connect test box for wiring test. Test Box, Connecting For Wiring Test

Vehicles with engine code AEG







- Check wires between test box and 4-pin connector (to control module) for open circuit according to wiring diagram.

Terminal 3 + socket 51
Terminal 4 + socket 52

Wire resistance: max. 1.5 Ohms

Vehicles with engine code AVH, AZG, BDC, BEV, BGD







- Check wires between test box and 4-pin connector (to control module) for open circuit according to wiring diagram.

Terminal 3 + socket 68
Terminal 4 + socket 69

Wire resistance: max. 1.5 Ohms

Continued for all vehicles
- Check wires for short circuit to B+ and to Ground (GND).

Specified value: Infinite Ohms

If no malfunctions are found in wires:
- Replace Motronic Engine Control Module (ECM) -J220-.