Symptoms
You probably won’t notice any driving issues because it’s not sensor number 1. You will notice the malfunction indicator lamp (MIL) lighting up. In some cases, however, the engine may run rough.
Potential Causes
Causes
of this DTC may include:
- Exhaust leak near the O2 sensor
- Contaminated or faulty HO2S2 (sensor 3)
- HO2S2 wiring/circuit problem
- Loose installation of HO2S2
- Incorrect fuel pressure
- Faulty fuel injector
- Engine coolant leak
- Faulty purge solenoid valve
- PCM failure
Diagnostic and Repair Procedures
Visually inspect the wiring and connectors for corrosion, rubbed/chafed/bent wires, bent/loose wiring pins, burnt appearance, and/or crossed wires. Repair or replace as needed. It would be a good idea to visually check the wiring of all sensors.
Check for exhaust leaks, repair if necessary.
Using a digital volt-ohmmeter (DVOM) set to ohms, check the resistance of the wiring harness connector(s). Compare to manufacturer specifications. Replace or repair as needed.
If you have access to an advanced scan tool, use it to monitor the sensor readings seen by the PCM (engine running, at normal operating temperature in closed-loop mode). Look at the reading for Bank 2, Sensor 3. The rear heated oxygen sensor (HO2S) normally sees a fluctuating voltage between 0 and 1 volt; for this DTC, you will likely see the voltage “stuck” at 0V. Revving the engine should cause the sensor voltage to change (react).
The most common fixes for this DTC appear to be either an exhaust air leak, a wiring issue with the sensor/wiring, or the sensor itself. If you replace the O2 sensor, buy an original one (manufacturer brand) for best results.
If you remove the HO2S oxygen sensor, inspect it for contamination from fuel, engine oil, and coolant.
Other troubleshooting ideas: use a fuel pressure tester, check the fuel pressure at the Schrader valve on the fuel rail. Compare to manufacturer specifications. Inspect the purge solenoid valve. Inspect the fuel injectors. Inspect coolant passages for leaks.
There may be Technical Service Bulletins (TSBs) that apply to your make and model regarding this fault code; check with your dealership or online source to locate specific TSBs that apply to your vehicle.