P0163: Oxygen sensor signal voltage reads too low, bank 2 sensor 3
O2 sensor circuit low voltage (bank 2, sensor 3)
Severity: Monitor
This is an oxygen sensor fault after the catalytic converter that mostly affects emissions monitoring, so the car can normally be driven while you book a check.
It gets more serious if:
- Inspect soon: Get it inspected soon if the engine runs rough, hesitates badly or stalls, since other faults may be involved.
P0163 in short
P0163 means the computer has found a low voltage in the circuit of the third oxygen sensor on bank 2 (three-sensor engines). The usual causes are a failed sensor or damaged wiring and connectors. The car is normally driveable, but the fault can hide other problems and will fail an emissions inspection, so get it checked.
The Delaware DMV list and TroubleCodes.net both define P0163 as an oxygen sensor fault on bank 2 (low voltage). Bank and sensor numbers come from the carmaker, so check service information for which sensor is which on your engine.
Reference pages say the sensor itself is the most common failure, with wiring and connector damage next. Sources describe the symptoms as mild; often only the warning light shows.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Failed or contaminated oxygen sensor
Common general cause- Why it ranks here
- TroubleCodes.net lists the sensor itself as a leading cause.
- What would change this
- Rises if the sensor signal is stuck or out of range on live data. Falls if the signal looks normal and moves.
Cause 2: Damaged or corroded wiring or connector
Common general cause- Why it ranks here
- TroubleCodes.net lists wiring and connector damage as the other main cause.
- What would change this
- Rises if the harness or plug shows damage or corrosion. Falls if wiring and connector are clean and intact.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all stored codes and note any other oxygen sensor codes stored with P0163.
IfSeveral oxygen sensor codes are stored
It meansA shared wiring or power problem is possible.
IfP0163 is the only code
It meansCheck the wiring and connector at the sensor.
Step 2: Look over the sensor wiring and connector for damage, burns or corrosion.
Warning:Exhaust parts are very hot after driving and a seized sensor can be damaged or break the thread when removed. Let the exhaust cool and have a shop do it.
IfWiring or connector is damaged
It meansRepair the wiring first.
IfWiring looks fine
It meansHave the sensor signal checked; a bad sensor is likely.
Symptoms
- Check engine light
- Failed emissions inspection
- No change in driving is usual; the check engine light is often the only sign
How to fix
Step 1: With the engine off and cool, look at the sensor connector and wiring for damage or corrosion.
Parts and cost context
- Oxygen (O2) sensor:Confirm which sensor is bank 2 sensor 3 on your engine. Labour varies; get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
We don't have reviewed vehicle-specific evidence for P0163 yet. The causes and tests above apply across vehicles.
Related codes
No curated relationships for P0163 yet.
P0163 questions
Which sensor is bank 2 sensor 3?
The third oxygen sensor on bank 2, on engines that have a third sensor per bank. Check your service information for its position.
Sources and review
- P0163 - Oxygen Sensor Circuit (Low Voltage)
- On-Board Diagnostic Trouble Codes (generic code title list)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error