P2A09

Symptoms

• Unstable engine operation at idle
• Increased fuel consumption
• Reduced engine power
• Check engine light comes on
• Failed Emissions Test Attempts

Causes

• Faulty oxygen sensor (lambda probe) Bank 2 Sensor 1
• Open or short circuit in the sensor signal wire
• Poor contact or corrosion in the electrical connector of the sensor
• Sensor or motor ground (ground) problems
• Engine control unit (ECU) internal failure (rare)

How to Fix

1. Visually inspect the sensor wiring and connector for damage and corrosion
2. Checking the voltage and resistance in the sensor circuit using a multimeter
3. Checking the reference voltage and sensor ground
4. Replacing a faulty oxygen sensor
5. Clearing error codes and performing a test run

Related codes

Error P2A09 by Vehicle Brand