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 is Ok.
• Oxygen Sensor Behind Three Way Catalytic Converter -G130- 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.

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 following Test-IDs.

-- Check the specified values at idle and compare the results to the min/max values given in the Mode 6 table.

If the specified values were obtained: 

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

If the specified values were Not obtained: 

Checking primary voltage 

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

-- 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 2.00 0 Volts

-- Switch the ignition Off.

If the specified value was obtained: 

-- Replace the Oxygen Sensor Behind Three Way Catalytic Converter -G130-.

If the specified value was Not obtained: 

Checking wiring 

-- Remove the Engine Control Module (ECM) -J623-.

-- 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 T91 terminals for an open circuit according to the chart below.

Oxygen Sensor Behind Three Way Catalytic Converter -G130- electrical harness connector terminal:	Engine Control Module (ECM) -J623- electrical connector T91 terminal:
3	26
4	25

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 found in the wiring and the voltage was NOT present: 

-- Replace the Engine Control Module (ECM) -J623-.

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 .