O2 Sensor Signal Shorted to Heater Circuit Bank 2 Sensor 2
The P2235 code indicates a short circuit between the oxygen sensor signal wire and the heater circuit for Bank 2 Sensor 2 (downstream sensor). This can cause incorrect voltage readings, leading to improper air-fuel mixture adjustments and potential catalytic converter damage. The issue is often due to damaged wiring, corrosion, or a faulty sensor.
1. Most Common Causes
- Internal short circuit in the oxygen sensor (between the sensor element and heater circuit)
- Damaged, pinched, or melted wiring harness (e.g., from contact with exhaust)
- Corroded, wet, or bent pins in the sensor or PCM connector
- Short to battery positive voltage in the wiring between the sensor and PCM
- Internal PCM failure (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Failed emissions test
- Possible rough idle or hesitation
3. Step-by-Step Diagnosis
Step 1: Scan for codes and confirm P2235. Check freeze frame data.
Step 2: Visually inspect wiring and connector for Bank 2 Sensor 2 for damage, corrosion, or shorts.
Step 3: Disconnect the sensor and measure resistance between heater pins and signal pin; if continuity exists, sensor is shorted internally.
Step 4: Check for voltage on signal wire with sensor disconnected; should be 0.45V. If voltage is present, repair short to heater circuit.
Step 5: Replace oxygen sensor if internal short is found, or repair wiring as needed.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause poor fuel economy and potential catalytic converter damage. 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 oxygen sensor itself costs $50-$150, and labor adds $50-$150.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.