P2236
O2 Sensor Signal Circuit Shorted to Heater Circuit Bank 2 Sensor 3
Fuel & air metering
Generic OBD-II
Low
What it means
P2236 means the ECM detected the oxygen sensor's signal wire shorted to its heater circuit on bank 2, sensor 3 — a rare third (deep downstream) position. It usually comes from chafed or heat-damaged wiring bridging the two circuits, or an internal short in the sensor. As a monitoring sensor, it affects emissions readiness far more than how the car drives.
Low
Can I keep driving? Drivable — this is a downstream monitoring sensor. It mainly affects emissions readiness rather than how the car runs.
Common symptoms
What you'll notice
- Check-engine light on
- Often no noticeable change in how the car drives
- Skewed O2 readings from the affected sensor
- Fails an emissions/readiness test
Common causes
Most likely first
- Signal and heater wires shorted together in the harness (chafed or pinched)Likely
- Internal short inside the bank 2, sensor 3 O2 sensorCommon
- Damaged or corroded sensor connector bridging the circuitsCommon
- Melted wiring from contact with the exhaustLess often
- Rarely, a faulty ECM/PCMLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm it's the bank 2, sensor 3 circuit.
- Inspect the sensor pigtail and harness for chafing, pinching, or heat damage bridging signal and heater wires.
- Disconnect the sensor and check whether the short clears — that isolates sensor vs. harness.
- Repair or reroute any damaged wiring away from hot exhaust components.
- If the harness is good but the short remains, replace the O2 sensor and retest.
FAQ
Quick answers
Is it safe to drive with P2236?+
Yes. This downstream sensor mainly reports emissions performance, so the car drives normally, but repair it to pass emissions.
Can I just clear P2236?+
It returns until the shorted wiring or sensor is repaired.
Related codes
Often seen with P2236
Read & clear P2236 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX