P2243

O2 Sensor Reference Voltage Circuit/Open Bank 1 Sensor 1

Q: Is it safe to drive with P2243?

It runs, but without the front sensor the ECM can't fine-tune fuelling, so economy suffers and it may run slightly rough. Fix it before it affects the catalytic converter.

Q: Can I just clear P2243?

It comes back while the circuit is open; the wiring or sensor must be repaired to restore closed-loop control.

Oxygen sensor Generic OBD-II Medium

What it means

P2243 means the reference-voltage circuit the ECM supplies to the front (bank 1, sensor 1) wideband oxygen sensor is open. Without that reference the sensor can't report the air-fuel ratio, so the engine falls back to open-loop fuelling. The car still runs, but economy and emissions suffer until the wiring or sensor is repaired.

Medium

Can I keep driving? Drivable, but with the front air-fuel sensor's reference lost the ECM runs open-loop — expect worse fuel economy and possibly rough running until it's fixed.

Real-world scan data

Seen in

137

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Poorer fuel economy (ECM runs open-loop)
Possible rough running or hesitation
Failed emissions readiness / test

Common causes

Most likely first

Open in the sensor's reference-voltage circuit wiringLikely
Faulty front wideband oxygen / air-fuel sensor (bank 1, sensor 1)Common
Poor or corroded connector at the sensorCommon
Faulty ECM reference supply (rare)Less often

How to diagnose & fix

Work through it in order

Inspect the bank 1 sensor 1 connector and wiring for an open in the reference circuit.
Check the reference voltage at the sensor connector with the key on.
Confirm the sensor grounds and signal wiring are intact.
Replace the front air-fuel sensor if the wiring is good but the reference is still open.
Clear and complete a drive cycle to verify closed-loop operation returns.

FAQ

Quick answers

Is it safe to drive with P2243?+

It runs, but without the front sensor the ECM can't fine-tune fuelling, so economy suffers and it may run slightly rough. Fix it before it affects the catalytic converter.

Can I just clear P2243?+

It comes back while the circuit is open; the wiring or sensor must be repaired to restore closed-loop control.

Read & clear P2243 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX