O2 Sensor Signal Shorted to Heater Circuit Bank 1 Sensor 1
The P2231 code indicates that the powertrain control module (PCM) has detected a short circuit between the oxygen sensor signal circuit and the heater circuit for Bank 1 Sensor 1 (upstream sensor). This can cause incorrect voltage readings, leading to improper air-fuel mixture adjustments and potential drivability issues. The short may be internal to the sensor or in the wiring harness.
01. Most Common Causes
- Faulty oxygen sensor (Bank 1 Sensor 1)
- Damaged wiring or connector causing short between signal and heater circuits
- Corrosion or moisture in the sensor connector
- PCM failure (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation during acceleration
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P2231 and check for other codes.
Step 2: Visually inspect the O2 sensor wiring and connector for damage, corrosion, or shorts.
Step 3: Disconnect the sensor and measure resistance between heater and signal pins; compare to specs.
Step 4: If wiring is intact, replace the oxygen sensor (Bank 1 Sensor 1).
Step 5: Clear codes and test drive to verify repair.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause poor engine performance and increased emissions. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost typically ranges from $150 to $300, including parts and labor. The sensor itself costs $50-$150, and labor adds $50-$150.