P0163 is an OBD-II trouble code indicating that the Engine Control Module (ECM/PCM) has detected a lower-than-expected voltage from the oxygen sensor circuit for Bank 2 Sensor 3.
Sensor 3 is not used on every vehicle. Therefore, the exact sensor location and circuit configuration depend on the vehicle's year, engine, and manufacturer.
P0163 Bank 2 Sensor 3 Location
On vehicles equipped with a Bank 2 Sensor 3, this sensor is generally located farther downstream in the exhaust system than Sensor 2. The exact position must be confirmed using the vehicle-specific service information or wiring diagram.
Bank 2
Normally refers to the cylinder bank opposite the bank containing cylinder number 1 on engines with two cylinder banks.
Sensor 3
Refers to the third oxygen sensor position used by the particular exhaust configuration.
Sensor 2 vs. Sensor 3
On applicable systems, Sensor 3 is generally positioned farther downstream than Sensor 2.
Important: Do not assume that every vehicle has Bank 2 Sensor 3. Confirm the sensor designation before beginning diagnosis.
P0163 Location by Manufacturer
The physical location of Bank 2 Sensor 3 can differ significantly between engines. Manufacturer-specific information should be treated as a guide rather than a universal location.
Chevrolet / GMC
On applicable multi-bank exhaust systems, inspect the oxygen sensor identified as Bank 2 Sensor 3 and its wiring for low voltage, damage, corrosion, or poor connections.
Toyota / Lexus
Sensor numbering varies by engine and emissions configuration. Confirm the exact sensor position and connector before testing or replacement.
Nissan / Infiniti
On applicable vehicles, inspect the specified Bank 2 Sensor 3 circuit and connector, particularly around the exhaust system where heat can damage the harness.
Jeep / RAM
Where Sensor 3 is used, inspect the downstream oxygen sensor circuit for wiring damage, moisture, corrosion, and loose connector terminals.
BMW
BMW sensor configurations vary by engine. Use the engine-specific wiring diagram to identify Bank 2 Sensor 3 and its signal circuit.
Ford
On applicable engines, verify the exact oxygen sensor designation before testing because sensor numbering depends on the exhaust configuration.
Symptoms of P0163
Check Engine Light
The Check Engine Light is commonly illuminated when P0163 is stored.
Increased Emissions
A low oxygen sensor signal can affect emissions monitoring and the engine control strategy.
Poor Fuel Economy
Fuel economy may be affected depending on the vehicle's control strategy and the underlying cause.
Rough Running or Hesitation
Some vehicles may experience drivability problems, although a downstream sensor fault does not always cause noticeable running symptoms.
Failed Emissions Test
A stored P0163 code can cause an emissions inspection failure in regions where OBD-II faults are checked.
Common Causes of P0163
Faulty Oxygen Sensor
The Bank 2 Sensor 3 may have an internal fault that causes its signal to remain lower than expected.
Short to Ground
A signal wire shorted to ground can pull the oxygen sensor voltage lower than expected.
Damaged Wiring
Broken, melted, corroded, or improperly repaired wiring can cause a low sensor signal.
Corroded Connector
Moisture, corrosion, loose terminals, or damaged connector pins can interfere with the sensor signal.
Exhaust Leak
An exhaust leak near the sensor can allow outside air into the exhaust stream and affect oxygen sensor readings.
Engine or Fuel Problem
An underlying rich or lean condition can influence oxygen sensor readings and should be considered during diagnosis.
Estimated Repair Cost for P0163
O2 Sensor Replacement
$100–$350 approximately, depending on the vehicle, sensor, and labor.
Wiring Repair
$50–$300 approximately depending on the location and extent of damage.
Connector Repair
$50–$200+ depending on the connector and labor required.
Exhaust Leak Repair
$100–$500+ depending on the location and parts required.
These are general estimates only. Actual repair costs vary by vehicle, parts, labor rate, and the cause of P0163.
How to Fix P0163
The correct repair depends on why the Bank 2 Sensor 3 signal is reading low. A sensor should not be replaced until the circuit and related engine conditions have been checked.
- Scan for additional stored and pending trouble codes.
- Confirm that the vehicle uses a Bank 2 Sensor 3 configuration.
- Verify the exact sensor location using the vehicle-specific wiring diagram.
- Inspect the sensor connector for corrosion, moisture, or loose terminals.
- Inspect the signal wiring for breaks, shorts, melting, or physical damage.
- Check sensor power and ground circuits where applicable.
- Check the oxygen sensor signal using appropriate scan-tool live data or electrical testing.
- Inspect for exhaust leaks near the sensor.
- Check for related fuel or engine problems that could affect the sensor reading.
- Replace the sensor if testing confirms an internal failure.
- Clear the code and verify the repair after the required drive cycle.
Common Repair Mistakes
Replacing the Sensor Immediately
P0163 does not automatically prove that the oxygen sensor itself has failed.
Ignoring a Short to Ground
A damaged signal wire can pull the sensor voltage low and cause the same code.
Testing the Wrong Sensor
Confirm Bank 2 Sensor 3 before performing electrical tests or replacing a component.
Ignoring Exhaust Leaks
An exhaust leak near the sensor can influence the oxygen reading and lead to an incorrect diagnosis.
Ignoring Other Codes
Additional fuel, misfire, or oxygen-sensor codes can provide important clues about the root cause.
Using an Incorrect Replacement Sensor
Verify the sensor specifications, connector, and compatibility with the specific vehicle.
Can You Drive With P0163?
If the vehicle is running normally and there are no severe drivability symptoms, it can usually be driven for a short period with P0163. However, the problem should be diagnosed promptly because the fault can affect emissions monitoring and may indicate an electrical or engine-related problem.
If the Check Engine Light is flashing, the engine is severely misfiring, or the vehicle has major performance problems, further diagnosis should be performed before continuing to drive.
Related OBD-II Codes
P0162
Bank 2 Sensor 3 Circuit Malfunction. Indicates a general circuit malfunction involving the same sensor.
P0164
Bank 2 Sensor 3 High Voltage. Indicates that the sensor circuit voltage is higher than expected.
P0165
Bank 2 Sensor 3 Slow Response. Indicates that the sensor response is slower than expected.
P0166
Bank 2 Sensor 3 No Activity Detected. Indicates insufficient activity from the specified oxygen sensor.
P0167
Bank 2 Sensor 3 Heater Circuit Malfunction. Indicates a problem with the heater circuit of the specified sensor.
Recommended Diagnostic Tools
OBD-II Scan Tool
Used to read P0163, additional codes, freeze-frame data, and oxygen sensor live data.
Digital Multimeter
Used to check voltage, ground, continuity, and possible shorts in the sensor circuit.
Vehicle Wiring Diagram
Helps identify the correct signal, power, ground, and ECM connections for Bank 2 Sensor 3.
O2 Sensor Socket
Useful for removing and installing the sensor after testing confirms that replacement is necessary.
P0163 FAQ
What does code P0163 mean?
P0163 means the ECM has detected a low voltage condition in the oxygen sensor circuit for Bank 2 Sensor 3.
Where is Bank 2 Sensor 3 located?
On vehicles that use Sensor 3, it is generally located farther downstream in the exhaust system than Sensor 2. The exact location varies by vehicle and engine.
Does every vehicle have Bank 2 Sensor 3?
No. Sensor 3 is application-dependent. Many vehicles use only Sensor 1 and Sensor 2 on a bank.
How do I fix P0163?
Confirm the correct sensor, inspect the wiring and connector, check for a short to ground, verify the sensor signal, inspect for exhaust leaks, and replace the sensor only when testing confirms an internal failure.
Is P0163 caused by a bad O2 sensor?
It can be, but a low signal can also result from damaged wiring, a short to ground, connector problems, exhaust leaks, or another engine or fuel-system problem.
Can P0163 cause poor fuel economy?
It can affect fuel economy on some vehicles, but the effect depends on how the vehicle's engine control system uses the affected sensor.
Can I drive with P0163?
A short drive is usually possible if the vehicle operates normally, but the fault should be diagnosed and repaired promptly.
Why does P0163 return after replacing the O2 sensor?
If the code returns after sensor replacement, the wiring, connector, signal circuit, exhaust system, and related engine conditions should be checked instead of replacing another sensor without testing.
Final Result
P0163 indicates a low-voltage condition in the Bank 2 Sensor 3 oxygen sensor circuit on applicable vehicles. The best diagnosis is to confirm the correct sensor, inspect the wiring and connector, check for a short to ground, verify the sensor signal, and investigate exhaust or engine conditions before replacing parts.