P2243 OBD-II Trouble Code: O2 Sensor Reference Voltage Circuit Open Bank 1 Sensor 1

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2243 code

P2243 is a diagnostic trouble code (DTC) for "O2 Sensor Reference Voltage Circuit Open Bank 1 Sensor 1". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $0.0 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford $0.0 $20.0
Toyota $0.0 $20.0
BMW $0.0 $20.0
SCHEDULE P2243 DIAGNOSTIC Get a fair and transparent estimate upfront

What the P2243 code means?

P2243 is an OBD-II generic code for the engine control module (ECM) detecting the O2 sensor for bank 1 sensor 1 having an open circuit for the reference voltage to the O2 sensor.

What causes the P2243 code?

  • The O2 sensor has an open circuit in the reference voltage circuit to the sensor or internal of the sensor.

  • The wiring or connector for the O2 sensor has an open circuit or corrosion in the connections.

What are the symptoms of the P2243 code?

  • The Check Engine light will be illuminated and the code is set in ECM memory as a fault.

  • The ECM will turn off the Check Engine light if three drive cycles pass without another failure.

  • The ECM may go into failure mode fuel control on most manufacturer vehicles. The ECM will go into open loop fuel control on some vehicles and not failure mode.

  • The engine may have different drivability symptoms like a lean surge, hesitation on acceleration, or a rough running engine.

How does a mechanic diagnose the P2243 code?

  • Scans for codes and documents the code in the ECM and looks at the freeze frame data for failure.

  • Checks the O2 sensor reference voltage circuit compared to the other O2 sensors to be the same reference voltage input.

  • Checks the O2 reference voltage circuit for open circuits in the sensor connector.

  • Tests the O2 sensor wiring is not shorted to the sensor ground.

  • Checks the wiring harness for open circuits from the O2 sensor to the ECM in the reference voltage signal from the ECM.

Common mistakes when diagnosing the P2243 code?

  • Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired

  • Failing to verify the reference voltage from the ECM before replacing the O2 sensor

  • Replacing all the O2 sensors when the problem is in the wiring harness

How serious is the P2243 code?

Code P2243 is a code indicating the O2 sensor reference voltage to the sensor is open and this will render the O2 sensor signal return inoperative and cause the ECM to go into open loop fuel control and turn on the Check Engine Light. This will also cause the vehicle to fail any emissions testing.

What repairs can fix the P2243 code?

  • Replace the O2 sensor for an open circuit in the reference voltage circuit.

  • Repair the wiring connector or wiring to the O2 sensor for open or corroded connections.

  • Replace the ECM if the reference voltage signal to the sensor is open in the ECM.

Additional comments for consideration regarding the P2243 code

Code P2243 is caused most commonly from an internal failure of the reference voltage circuit inside the O2 sensor. The O2 sensor wiring cover is also a vent on some O2 sensors and if the cover is cut or removed then the sensor can get water into the back side of the sensor and cause it to short out the circuit and blow the O2 sensor reference circuit in the ECM.

Need help with a P2243 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

Check Engine Light
trouble codes
P2243

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P2243 code.

SCHEDULE P2243 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(6830)

Rating Summary
6333
239
54
37
167
6333
239
54
37
167
 at YourMechanic

Pedro

31 years of experience
54 reviews
Pedro
31 years of experience
Nissan Altima L4-2.5L - Check Engine Light is on - Chicago, Illinois
He came before his time which was awesome. He explained everything to me that was wrong so that I can understand better
 at YourMechanic

Andrew

26 years of experience
19 reviews
Andrew
26 years of experience
Hyundai Elantra L4-1.8L - Check Engine Light is on - Las Vegas, Nevada
Great mechanic. Honest and trusting. Very happy about choosing Your Mechanic, definitely using Andrew for future work.
 at YourMechanic

Richard

35 years of experience
61 reviews
Richard
35 years of experience
Mazda 3 L4-2.3L - Check Engine Light is on Inspection - Port Richey, Florida
Richard was great! He was able to find my problem immediately and offer a solution with in minutes. I would definitely reccomend and request him for my future maintenance needs.
 at YourMechanic

Corey

16 years of experience
239 reviews
Corey
16 years of experience
Honda Civic L4-1.7L - Check Engine Light is on - Kannapolis, North Carolina
Corey is always great at finding the root of the problem and only recommending services that are necessary. I will continue to request Corey to fix my 17 year old car that is prone to issues at over 200,000 miles.


More related articles

P0614 OBD-II Trouble Code: ECM / TCM Incompatible
P0614 code means there has been an error in compatibility between the car’s engine control module and TCM often due too corrosion, or bad PCM.
P2344 OBD-II Trouble Code: Cylinder #9 Above Knock Threshold
P2344 means an issue with the cylinder 9 knock sensor circuit. Some causes are faulty knock sensor, damaged wires, and cylinder firing malfunctions.
P0642 OBD-II Trouble Code: Sensor Reference Voltage “A” Circuit Low
P0642 means there is an abnormally low voltage reading within the "A" circuit often due too a faulty engine control module or other malfunctions.

Related questions

Check Engine Light came on

It sounds like you have a pretty bad misfire. While a faulty O2 sensor could be the cause, it is not the most likely. A misfire happen can be caused by anything that prevents the air/fuel mixture from igniting properly...

Why does the check engine light keep coming back on?

The check engine light comes on and stays on if the onboard computer sees a problem that could cause an increase in emissions or a problem with its systems. After looking at most of the possible codes or issues that...

Code p0128

Code P0128 is engaged specifically when the engine itself does not get to operating temperature in a specified time period. The only things that can cause this problem is an issue with the thermostat, head temp sensor, and the coolant...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com