P2379 code meaning
O2 Sensor Out of Range During Deceleration (Bank 2 Sensor 2)
Powertrain system Generic code P23xx codes Check engine light
What P2379 means
P2379 covers the oxygen sensor behind the catalyst on bank 2 at the moment the injectors are shut off on a closed throttle: the exhaust is then close to fresh air, and a sensor whose reading stays outside the expected lean window is suspect. No manufacturer documents P2379 publicly. The nearest published logic is GM's bank 1 code P232F on the 2023 6.6L L5P, which compares the O2 value of the rear NOx sensor with the front one during overrun (window +3.01 to −3.18 %, Type B); that engine has no second bank. Ford checks the same sensor during fuel cut but reports under P013C, P014A or P2272/P2273. CARB asks at least for a rich-to-lean check of rear sensors in fuel shut-off. Code lists also give P239F this title. The car drives normally; the light points to sensor ageing or an exhaust leak.
P2379 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P2379
- Check engine light on
- No noticeable change in how the car drives
- Downstream O2 reading on bank 2 stays high during coasting in live data
Common causes of P2379
- Most likelyBank 2 downstream sensor aged or contaminated, reacting too little to fuel cut
- PossibleExhaust leak near the bank 2 rear sensor diluting or distorting the sample
- PossibleChafed sensor lead or corroded connector on the bank 2 rear sensor
- Less likelyLeaking injector on bank 2 keeping fuel in the exhaust during overrun
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor b2s2Exhaust after catalyst b2
What each part of P2379 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 3 | Area: ignition system or misfire. |
| 79 | The exact fault in that area. |
What to do next
- Note P2379 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 P2379
What does P2379 mean?
P2379 means "O2 Sensor Out of Range During Deceleration (Bank 2 Sensor 2)". P2379 covers the oxygen sensor behind the catalyst on bank 2 at the moment the injectors are shut off on a closed throttle: the exhaust is then close to fresh air, and a sensor whose reading stays outside the expected lean window is suspect. It is a generic code, so it means the same on every make.
Is it safe to drive with P2379?
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 P2379 fail an emissions test?
Yes, it can. P2379 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 P2379 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2379 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.