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 current in the pumping current trim circuit of the oxygen sensor located in Bank 1, Sensor 1 (pre-cat). This circuit is part of the wideband air-fuel ratio sensor, which uses a pumping current to measure oxygen content. A high signal suggests a short to voltage, open circuit, or a faulty sensor, leading to incorrect air-fuel mixture readings.
01. Most Common Causes
- Faulty oxygen sensor (Bank 1, Sensor 1)
- Short to voltage in the sensor wiring or connector
- Open circuit in the sensor signal or ground wire
- Corroded or damaged sensor connector
- ECM internal fault (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation
- Failed emissions test
03. 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 shorts.
Step 3: Test the sensor's heater circuit and signal voltage using a multimeter.
Step 4: Compare sensor readings with a known good sensor or use a scan tool to monitor live data.
Step 5: If wiring and sensor are okay, test the ECM output to the sensor circuit.
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 the incorrect air-fuel mixture can cause poor performance, reduced fuel economy, and potential damage to the catalytic converter.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a DIY replacement of the oxygen sensor, or $150 to $300 if professionally diagnosed and replaced.