O2 Sensor Circuit Low Voltage (Bank 2 Sensor 3)
The P0163 code indicates that the oxygen sensor (O2) located after the catalytic converter on Bank 2 (the side of the engine not containing cylinder #1) is reporting a voltage lower than the expected range (typically below 0.1 volts). This sensor monitors the efficiency of the catalytic converter. A low voltage reading can be caused by a faulty sensor, wiring issues, exhaust leaks, or a rich fuel mixture. This code is specific to vehicles with OBD2 systems and often triggers the Check Engine Light.
01. Most Common Causes
- Faulty oxygen sensor (Bank 2 Sensor 3)
- Open or shorted wiring in the sensor circuit
- Exhaust leak near the sensor
- Engine running rich (excess fuel) causing low voltage
- Faulty PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Decreased fuel economy
- Failed emissions test
- Possible rough idle or hesitation
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other related codes.
Step 2: Visually inspect the wiring and connector for Bank 2 Sensor 3 for damage, corrosion, or loose connections.
Step 3: Check for exhaust leaks near the sensor by listening for hissing or using a smoke machine.
Step 4: Test the sensor's voltage output with a multimeter while the engine is running; compare to manufacturer specifications.
Step 5: If voltage is low and wiring is intact, replace the oxygen sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances, but it may cause poor fuel economy and could damage the catalytic converter over time. It's best to diagnose and fix promptly.
How much does it cost to fix?▼
The cost typically ranges from $150 to $300, including parts and labor. The sensor itself costs $50-$150, and labor adds $50-$150.