Heated Oxygen Sensor After Catalytic Converter, Checking
This procedure is used to check both Heated Oxygen Sensors (HO2S) --G130-, -G131--
When servicing terminals in harness connector of oxygen sensor, use only gold-plated terminals.
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test Requirements
- Fuses -- for engine electronics OK.
- Battery voltage at least 12.5 V.
- All electrical consumers such as, lights and rear window defroster, switched off (radiator fan must NOT run during test).
- Ground (GND) connections between engine/transmission/chassis OK.
- Oxygen sensor heater OK.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- The exhaust system free of leaks.
- The parking brake engaged.
- The A/C switched off.
- The coolant temperature at least 80 °C.
- Ignition switched off.
Test Procedure
-- Perform a preliminary check to verify the customer's complaint. Refer to PRELIMINARY CHECK .
-- Perform the function test in Diagnostic Mode 06. Refer to DIAGNOSTIC MODE 06 - READ TEST RESULTS FOR SPECIFIC DIAGNOSTIC FUNCTIONS .
If specified values are obtained:
-- End diagnosis and switch the ignition off.
If the specified values are not obtained:
Checking primary voltage
-- Disconnect the 4-pin electrical harness connector -2- from Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- and Oxygen Sensor (O2S) Heater --Z29-- (bank 1, sensor 2).
-- Remove the screw -arrow- retaining the coolant reservoir.
-- Disconnect the electrical connector from Engine Coolant Level (ECL) Warning Switch -F66- at the bottom of the coolant reservoir and set aside the coolant reservoir with the coolant hoses -1- and -2- connected.
-- Disconnect the electrical 4-pin harness connector -2- from Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131- and Oxygen Sensor (O2S) Heater 2 (behind Three Way Catalytic Converter (TWC)) -Z30- (bank 2, sensor 2).
-- Using a Multimeter, check the electrical harness connector terminals 3 to 4 for voltage.
-- Switch ignition on.
Specified value: 0.400 to 0.500 V
-- Switch ignition off.
If specified value is obtained:
-- Replace Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- or Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131-. Refer to Component Locations Overview .
If specified value is not obtained:
Checking wiring
If the manufacturers test box is being used, perform the following step.
-- Connect the Test Box 105 Pin VAG1598/42 with Adapter Cable1598/39-1. Refer to Component Locations Overview
If the manufacturers test box is not being used, perform the following step.
-- Remove the Engine Control Module (ECM) -J623-. Refer to ENGINE CONTROL MODULE, REPLACING
Using a Multimeter --, check the Heated Oxygen Sensor (HO2S) 2 -G108- electrical harness connector terminals to the Engine Control Module (ECM) -J623- electrical harness connector terminals for resistance.
- Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-
| Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC)G130 Electrical Harness Connector Terminal | Engine Control Module (ECM)J623 Electrical Harness Connector Terminal or Test box Socket |
|---|---|
| 2 | 75 |
| 3 | 76 |
| 4 | 77 |
- Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G131-
| Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC)G131 Electrical Harness Connector Terminal | Engine Control Module (ECM)J623 Electrical Harness Connector Terminal or Test box Socket |
|---|---|
| 2 | 91 |
| 3 | 54 |
| 4 | 55 |
Specified value: 1.5 Ω max.
If the specification is not obtained:
-- Check the wiring for a short circuit to Battery positive (+) or an open circuit.
-- If necessary, repair the wiring connection.
If no malfunctions are found in wiring:
-- Replace Heated Oxygen Sensor (HO2S) --G130-- or Heated Oxygen Sensor (HO2S) --G131--. Refer to Component Locations Overview .
-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
-- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Refer to READINESS CODE .
-- End diagnosis.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
-- Replace the Engine Control Module (ECM) -J623-. Refer to ENGINE CONTROL MODULE, REPLACING .
-- Assembly is performed in the reverse of the removal.
After repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .