Oxygen Sensor and Sensor Control After Converter, Checking
Oxygen Sensor And Oxygen Sensor Control Behind Three Way Catalytic Converter (TWC), Checking
NOTE: When servicing terminals in harness connector of Heated Oxygen Sensor (HO2S), use only goldplated terminals.
Recommended special tools and equipmen
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram
Test requirements
- The respective fuses of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- and Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131- must be OK.
- Battery voltage must be at least 11.5 volts.
- All electrical consumers like, for example, lights and rear window heating must be switched off.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- 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 degree C, Diagnostic mode 1: Check measuring values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measuring Values
- Oxygen sensor heater for oxygen sensors behind catalytic converter must be OK, check.
Function test
- Select the following output of oxygen sensor signals and check whether the specified values are being reached, Diagnostic mode 5: Check output of oxygen sensor signals. Diagnostic Mode 5: Check Output of Oxygen Sensor Signals
- Check the specified values of the output of oxygen sensor signals at idle:
*) V = Voltage in Volts (oxygen sensor signal)
**) t = Time in seconds
Continuation for all vehicles
NOTE:
- Cylinder bank 1 = in driving direction, right
- Cylinder bank 2 = in driving direction, left
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
- Disconnect 4-pin harness connector to the respective oxygen sensor:
Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) - G130-, bank 1, 4-pin harness connector (green) (arrow).
Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131-, bank 2, 4-pin harness connector (brown, arrow).
- Connect multimeter for voltage measurement to terminals 3 & 4 of the respective connector to Engine Control Module (ECM) and measure primary voltage.
Specified value: 0.40 to 0.50 volts
- Switch ignition off.
If specified value is not obtained on one or both Heated Oxygen Sensors (HO2S):
- Test oxygen sensor wires.
If specified values are obtained:
- Replace the respective oxygen sensor:
- Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-, bank 2
- Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131-, bank 2
- 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. Readiness Code, Generating
Checking oxygen sensor wires
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test
- Check wires between test box and 4-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Wire resistance: max: 1.5 Ohm
Continuation for all vehicles
- Also check wires for short circuit to B+ and Ground (GND).
Specified value: Infinite Ohm
If no wiring faults are found:
- Replace Motronic Engine Control Module (ECM) -J220-.