Oxygen Sensor Behind Catalytic Converter, Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• The Oxygen Sensor Behind Three Way Catalytic Converter -G130- fuse OK.
• Oxygen Sensor 1 behind Three Way Catalytic Converter Heater - Z29- OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, selector lever in position "P" or "N".
• A/C switched off.
• Ground connections between engine/transmission/chassis OK.
• Exhaust system between catalytic converter and cylinder head properly sealed.
• Coolant Temperature at least 80 °C.
• Ignition switched OFF.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK 

Start diagnosis 

-- Connect scan tool.

-- Start the engine and let it run at idle.

-- Select "Diagnostic mode 6: Check test results of components that are not continuously monitored".

-- Select "Monitor-ID $02: Oxygen sensor monitoring behind catalytic converter".

-- Select a Test-ID.

-- Check the specified values at idle.

-- Turn the ignition switch OFF.

If the specified values were obtained:

-- Fault is not active at this time. Check for poor connections, loose terminals and harness check.

If any of the specifications were Not obtained:

-- Remove the right vehicle floor cover -arrows-.

Checking primary voltage 

-- Disconnect the Oxygen Sensor Behind Three Way Catalytic Converter -G130- electrical harness connector -arrow-.

-- Switch the ignition ON.

-- Using a multimeter, check the Oxygen Sensor Behind Three Way Catalytic Converter -G130- electrical harness connector terminals 3 to 4 for voltage.

Specified value: 0.400 to 0.500 Volts

-- Switch the ignition OFF.

If the specified value was obtained:

-- Replace the Oxygen Sensor Behind Three Way Catalytic Converter -G130-. Refer to the Repair information.

If the specified value was Not obtained:

Checking wiring 

-- Remove the Engine Control Module (ECM) -J623-. Refer to the Repair information.

-- Using a multimeter, check the Oxygen Sensor Behind Three Way Catalytic Converter -G130- electrical harness connector terminals to the Engine Control Module (ECM) -J623- electrical harness connector T94 terminals for an open circuit according to the wiring diagram.

Heated Oxygen Sensor (HO2S) -G39- electrical harness connector terminal:	Engine Control Module (ECM) -J623- electrical connector T94 terminal:
3	34
4	62

Specified value: 1.5 Ω Max.

If the specified value was Not obtained:

-- Check the wiring for an open, high resistance or short to ground.

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and the voltage supply was Not OK:

-- Replace the Engine Control Module (ECM) -J623-. Refer to the Repair information.

-- Install the right vehicle floor cover -arrows-.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .