Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. P2231 OBD-II Trouble Code: O2 Sensor Signal Circuit Shorted to Heater Circuit Bank 1 Sensor 1

P2231 OBD-II Trouble Code: O2 Sensor Signal Circuit Shorted to Heater Circuit Bank 1 Sensor 1

Check Engine Light

P2231 code definition

O2 Sensor Signal Circuit Shorted to Heater Circuit Bank 1 Sensor 1

What the P2231 code means

P2231 is an OBD-II generic code for the engine control module (ECM) detecting the O2 sensor signal is shorted to the heater circuit on bank 1 sensor 1.

What causes the P2231 code?

  • The engine control module (ECM) monitors the O2 sensor bank 1 sensor 1 signal wire and is expecting only about 1.2 volts maximum. When the ECM sees a return voltage above 1.2 volts, it knows the sensor is shorted to the heater circuit that is running battery voltage. When it sees the short, the ECM turns on the Check Engine Light and the P2231 code is set.

  • The O2 sensor is shorted internally or the wiring is shorted.

What are the symptoms of the P2231 code?

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

  • The ECM will ignore the O2 sensor and use all the other O2 sensors to try and control the fuel or it will go into open loop fuel control.

  • The engine may hesitate on acceleration.

  • The fuel mileage may be more than before failure.

How does a mechanic diagnose the P2231 code?

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

  • Monitors the O2 sensors for bank 1 sensor 1 to see if the signal is shorted to the heater circuit.

  • Inspects the O2 sensor and the wire harness for any damage that could cause the short.

  • Follows the manufacturer pinpoint tests for the diagnosis and replacement of the O2 sensor if the O2 sensor is internally shorted.

Common mistakes when diagnosing the P2231 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 clear the ECM codes after the codes are fixed so the ECM will enable the system to control the fuel again.

How serious is the P2231 code?

Code P2231 is a code indicating the engine cannot control the fuel since it cannot go into a closed loop on bank 1. This will cause the engine to fail emissions testing and the engine to not run as efficient as it can.

What repairs can fix the P2231 code?

Additional comments for consideration regarding the P2231 code

Code P2231 is for a short in the bank 1 sensor 1 O2 sensor. The most common problems that cause this are issues with the sensor wiring or the sensor being contaminated by an oil leak. The short can also be from a harness that comes loose and melts on the exhaust. The sensor shorting is that last problem to look for. If an oil leak is the cause of the problem, then make sure you replace the O2 sensor and repair the oil leak so the problem will not happen again anytime soon.

Need help with a P2231 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...


Related questions

Q: Check Engine Light came on. Car also has problems cranking but only when I refill it with gas.

Hi there - the first thing to do is extract the problem code(s) which are setting the "Check Engine" light. This will more efficiently direct resolution of the problem. Evaporative emission system problems are often associated with "fill-up" issues like...

Q: Fuel is leaking and Check Engine Light is on - 2008 Mazda 3

The fuel pump is contained within the tank and so cannot leak. You are probably seeing fuel leaking from a fuel line and/or from the fuel tank itself. There could be a loose fuel line fitting, impact damage (debris from...

Q: Error code P2187 - 2013 Hyundai Elantra

Hello - the P2187 code indicates a fuel/air mixture that is too lean. This could be caused by a leak in the air intake (the plastic intake tube might be cracked for example), a loose hose on the air intake,...