O2 Sensor Pumping Current Trim Circuit High Bank 1 Sensor 1
The P2628 code indicates that the Engine Control Module (ECM) has detected a high voltage or resistance in the pumping current trim circuit of the oxygen sensor located in Bank 1, Sensor 1 (upstream of the catalytic converter). This circuit is responsible for adjusting the sensor's pumping current to maintain the proper air-fuel ratio. A high condition suggests an open circuit, high resistance, or a short to voltage, which can cause incorrect fuel trim adjustments and poor engine performance.
1. Most Common Causes
- Faulty oxygen sensor (Bank 1, Sensor 1)
- Open or shorted wiring in the sensor circuit
- Corroded or damaged connector
- ECM malfunction (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation
- Failed emissions test
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the O2 sensor wiring and connector for damage, corrosion, or loose connections.
Step 3: Test the sensor's pumping current circuit using a multimeter; compare readings to manufacturer specifications.
Step 4: If wiring is intact, replace the oxygen sensor (Bank 1, Sensor 1).
Step 5: Clear codes and test drive to verify repair.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe for short distances, but prolonged driving may cause poor fuel economy, reduced performance, and potential damage to the catalytic converter. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a DIY replacement of the oxygen sensor. Professional repair may cost $100 to $300 including parts and labor.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.