P2273 code meaning
O2 Sensor Signal Biased/Stuck Rich (Bank 2, Sensor 2)
Powertrain system Generic code P22xx codes Check engine light
What P2273 means
P2273 means the rear oxygen sensor of bank 2 keeps a high voltage when the exhaust of that bank should be lean. GM's 2016 tables (16OBDG05) check this in fuel cut-off and set the code if the signal is above 100 mV after 9 g of air (Type B); GM's 2024 tables (24OBDG07) compare the lowest voltage during a commanded lean phase with 0.20 V over two trips. The Bosch-based 2005 GM V6 leans the bank after a long high-voltage phase and also fails the sensor above 0.202 V four seconds into a fuel cut. Ford treats bank 2 like bank 1 and uses fuel-cut events from model year 2019. Typical causes are a sensor fouled by oil or coolant on that side or a signal wire touching a supply line. P2099 is the post-catalyst trim of bank 2 at its rich limit; P0158 a voltage above the normal range.
P2273 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P2273
- Malfunction indicator lamp on
- Catalyst monitor for bank 2 not completing
Common causes of P2273
- Most likelyBank 2 rear oxygen sensor fouled by oil or coolant
- Less likelySignal wire touching a supply or heater line
- Less likelyBank 2 front sensor misreading so that the bank actually runs rich
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor downstreamOxygen sensor wiring
What each part of P2273 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 2 | Area: fuel and air metering (injector circuit). |
| 73 | The exact fault in that area. |
What to do next
- Note P2273 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2273
What does P2273 mean?
P2273 means "O2 Sensor Signal Biased/Stuck Rich (Bank 2, Sensor 2)". P2273 means the rear oxygen sensor of bank 2 keeps a high voltage when the exhaust of that bank should be lean. It is a generic code, so it means the same on every make.
Is it safe to drive with P2273?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2273 fail an emissions test?
Yes, it can. P2273 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2273 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2273 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.