Oxygen Sensor Heaters After Catalytic Converter, Checking
The following procedure is used to diagnose Oxygen Sensor (O2S) 1 (behind Three Way Catalytic Converter (TWC)) Heater - Z29- for Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- and Oxygen Sensor (O2S) 2 (behind Three Way Catalytic Converter (TWC)) Heater -Z30- for Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131-.
Vehicle must be raised before electrical harness connector for the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- and Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131- is accessible.
When servicing terminals in harness connector of Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- and Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131-, use only gold-plated terminals.
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- The Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- and Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131- fuse OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.
Test procedure
-- Perform a preliminary check to verify the customers complaint. Refer to GENERAL DIAGNOSIS .
Start diagnosis
-- Remove the right vehicle floor cover -arrows-.
Checking internal resistance
-- Disconnect the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130- electrical harness connector -1- or the Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131- electrical harness connector -2-.
-- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -- terminals 1 to 2 for resistance.
Specified value: 1.0 to 20.0 Ω (at approx. 20° C)
If the specification was not obtained:
-- Replace the faulty Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) --.
If the specification was obtained:
Checking voltage supply
-- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) - G130- electrical harness connector terminal 1 to the Fuel Pump (FP) 2 Relay -J49- -R4- terminal 2/87 for an open circuit.
| Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) - G130- electrical harness connector terminal | Fuel Pump (FP) 2 Relay -J49- electrical harness connector terminal |
|---|---|
| 1 | 2/87 |
Specified value: Battery voltage.
If the specification was not obtained:
-- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
-- Check the electrical harness connector for damage, corrosion, lose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If the specification was obtained:
Checking Ground (GND) activation
If the manufacturers test box is being used. Perform the following step.
-- Install the test box. Refer to Repair information.
If the manufacturers test box is not being used. Perform the following step.
-- Remove the Motronic Engine Control Module (ECM) -J220-. Refer to MOTRONIC ENGINE CONTROL MODULE, REPLACING .
-- Using a multimeter, check the Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -- electrical harness connector to the Motronic Engine Control Module (ECM) -J220- electrical harness connector T121 for an open circuit.
| Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) - G130- electrical harness connector terminal | Motronic Engine Control Module (ECM) -J220- electrical connector T121 terminal or test box socket |
|---|---|
| 2 | 63 |
| Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131- electrical harness connector terminal | Motronic Engine Control Module (ECM) -J220- electrical connector T121 terminal or test box socket |
|---|---|
| 2 | 6 |
Specified value: 1.5 Ω max.
If the specification was not obtained:
-- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
-- Check the electrical harness connector for damage, corrosion, lose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring and if the voltage supply was OK:
-- Replace the Motronic Engine Control Module (ECM) -J220-. Refer to MOTRONIC ENGINE CONTROL MODULE, REPLACING .
-- Install the right vehicle floor cover.
Final procedures
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 .
-- End of diagnosis.