P2243 code meaning
O2 Sensor Reference Voltage Circuit/Open (Bank 1 Sensor 1)
Powertrain system Generic code P22xx codes Check engine light
What P2243 means
P2243 flags an open reference voltage line on the front wide-band sensor of bank 1, i.e. the Nernst-cell lead (RE/UN on Bosch sensors, VS on NTK). Ford's OBD summaries set it on Bosch parts when the sensor voltage sits above 4.7 V or below 0.2 V for 10 s; on NTK parts the interface chip reports the break itself. GM's 2005 V6 tables and the 2010 Saab 9-5 2.0 turbo use the same voltage window with cell resistance above 570 ohms, as a two-trip Type B code. On the 2004-05 Saturn Vue 3.5 V6 the pump-cell voltage must swing both above 4.8 V and below 3.4 V fifty times. Honda bulletin 14-002 ties it on 2010-11 V6 models to a broken sensor tip, often with P0420/P0430; Ford reflashes the 2020 Explorer 2.3 (20-2217). P2247 is bank 2, P2245/P2246 low/high.
P2243 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 repairWhen cleared with a scanner
Symptoms of P2243
- Check engine light
- Higher fuel consumption from open-loop fuelling on bank 1
- Catalyst efficiency code P0420 alongside it if a sensor fragment damaged the converter
Common causes of P2243
- Most likelyBroken reference voltage (Nernst cell) wire or pushed-back pin between sensor and ECM
- PossibleSensing element cracked or tip broken off, for example by thermal shock
- Less likelyCorroded or loose sensor connector
- Less likelyEngine software that sets the code falsely (update available for some models)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor bank1 sensor1Oxygen sensor wiringECM
What each part of P2243 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). |
| 43 | The exact fault in that area. |
What to do next
- Note P2243 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 P2243
What does P2243 mean?
P2243 means "O2 Sensor Reference Voltage Circuit/Open (Bank 1 Sensor 1)". P2243 flags an open reference voltage line on the front wide-band sensor of bank 1, i.e. It is a generic code, so it means the same on every make.
Is it safe to drive with P2243?
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 P2243 fail an emissions test?
Yes, it can. P2243 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 P2243 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 P2243 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.