Heated Oxygen Sensor HO2S, Bank 1, Sensor 1, Checking
Heated Oxygen Sensor HO2S, Bank 1, Sensor 1, Checking
Observe all safety precautions: => [ Safety Precautions ] Generic Scan Tool
View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions
For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.
• Use only gold-plated terminals when servicing terminals in the electrical harness connector of the Heated Oxygen Sensor (HO2S) (G39).
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• The Oxygen Sensor (O2S) Heater (Z19) fuse OK.
• The Oxygen Sensor (O2S) Heater (Z19) before catalytic converter OK. Refer to => [ Oxygen Sensor O2S Heater, Bank 1, Sensor 1, Checking ] Oxygen Sensor O2S Heater, Bank 1, Sensor 1, Checking.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• A/C switched off.
• Ground (GND) 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 ] Preliminary Check
Start diagnosis
- Connect scan tool.
Start diagnosis
- Remove the engine covers. Refer to the appropriate service manual.
- Start the engine and let idle.
- Select "Diagnostic mode 6: Check test results of components that are not continuously monitored".
- Select "Test-ID 01: Oxygen sensor monitoring before catalytic converter".
- Select "Test-ID 131: Dynamic test".
- Check the specified values at idle.
• For connector location, removal and installation procedures. Refer to the appropriate service manual.
If the specified value was obtained:
- Fault may be intermittent.
- Check for loose or corroded connections and any leaks in the exhaust.
- Check Freeze Frame data for conditions when the DTC set.
- Go to Final procedures
If the specified value was Not obtained:
Checking voltage
- Disconnect the Heated Oxygen Sensor (HO2S) (G39) / Oxygen sensor heater (Z19) electrical harness connector - 2 -.
- Using a Multimeter, check the Heated Oxygen Sensor (HO2S) (G39) electrical harness connector terminals 1 to 6 for voltage.
- Switch the ignition ON.
Specified value: 0.400 to 0.500 Volts
- Switch the ignition OFF.
If the specified value was obtained:
- Replace the Heated Oxygen Sensor (HO2S) (G39). Refer to the appropriate service manual.
- Go to Final procedures
If the specified value was Not obtained:
Checking wiring
- Remove the Motronic Engine Control Module (ECM) (J623). Refer to the appropriate service manual.
- Using a multimeter, check the Heated Oxygen Sensor (HO2S) (G39) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T94 terminals for an open circuit.
Specified value: 1.5 ohms Max.
If the specified value was Not obtained:
- Check the wiring for a short circuit to Battery (+), or an open circuit.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
- Go to Final procedures
If the specified value was obtained:
- Replace the Engine Control Module (ECM) (J623). Refer to the appropriate service manual.
Final procedures
- Reinstall the engine covers, if necessary. Refer to the appropriate service manual.
- For connector location, removal and installation procedures. Refer to the appropriate service manual.
- 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 ] Diagnostic Modes 01 - 09.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.