OBD-II code family
Oxygen Sensor Signals Shorted to Heater Circuits (6 codes)
6 related fault descriptions. Use each full code and the exact vehicle service information to identify its circuit, monitored condition, and required tests.
Codes in this family
This is the complete published member list for this guide. Each code retains its own page; shared diagnostic context does not mean that every member has the same test or repair.
- P2231O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 1, Sensor 1)
- P2232O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 1, Sensor 2)
- P2233O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 1, Sensor 3)
- P2234O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 2, Sensor 1)
- P2235O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 2, Sensor 2)
- P2236O2 Sensor Signal Circuit Shorted to Heater Circuit (Bank 2, Sensor 3)
What these codes mean
These six entries compare the oxygen-sensor signal-to-heater short category across Bank 1 and Bank 2, Sensors 1, 2 and 3. The identifiers select a diagnostic position; they do not establish a converter count, the total number of sensors, the hardest access or a shared wiring route. Resolve the complete report and actual exhaust/sensor layout before accessing or ordering a part.
The April 2002 SAE group note describes both switching and wide-band sensors with PWM-controlled heaters and relates the signal behavior to heater operation. It does not make wire count a universal sensor-type test or one displayed voltage a conclusive short diagnosis. A controller’s bias, scan-tool representation and the required test state must be understood.
The dated manufacturer examples illustrate different evaluations. The 2013 Audi A8 4.0L CEUA/CGTA chart gives timed front-signal-change criteria for P2231/P2234. The archived 2009 Saturn Outlook 3.6L P2232/P2235 procedure evaluates signal changes associated with heater switching and has its own prerequisites and bias/circuit checks. Keep those application-specific methods separate from a generic unplug-or-replace rule.
Position alone does not certify fueling or catalyst health. Preserve mixture, misfire and catalyst reports and evaluate their evidence rather than assuming every companion is caused by the short. A normal reading or trim on one bank does not clear genuine air, fuel or electrical concerns on the other, and an opposite-bank sensor is not automatically an identical reference part.
Review previous sensor, exhaust and harness work against the actual part number and routing requirements. Evidence of a wrong part, damaged insulation, a contaminated connector or a failed retaining clip can guide diagnosis; no sensor number establishes the most likely cause. Confirm whether the affected section is vehicle wiring, an integral lead, a connector or the assembly itself before approving repair or replacement.
Have qualified personnel use the permitted signal, heater, reference and controller-input checks after the specified cooling and isolation. Do not improvise a live pin test, jumper, generic test lamp or resistance verdict. Repair the demonstrated fault and complete the prescribed verification. Then assess any remaining mixture, misfire or catalyst concerns on their own evidence.
Follow actual warnings and symptoms. These labels do not establish inevitable engine damage at every upstream position or harmless driving at every rear position. Stop safely for severe running problems, flashing warnings, exhaust fumes or unsafe response. A useful quote specifies the confirmed fault, serviceable wiring or assembly, labor and setup; the code does not automatically price a sensor, controller or converter.
Identify the circuit on your vehicle
Match the full DTC, reporting module, and any failure-type suffix to the service information for your exact year, make, model, engine, and equipment. An identifier alone does not establish installed hardware count, location, connector pinout, or a universal measurement.
Where the manufacturer publishes its own meaning for this code, that is the one to work from — it describes the actual component on your vehicle, which the generic definition cannot. Keep the generic description for what it is good for: it tells you which subject area the standard assigned the code to, which is useful context when the two appear to disagree. If they do disagree, follow the manufacturer.