Insufficient coolant temperature for closed loop fuel control?

Answer 1

• Insufficient warm up time
• Low engine coolant level
• Leaking or stuck open thermostat
• Faulty coolant temperature sensor

Check your coolant level first.

Reset the code and see if it comes back.

Replace thermostat.

However, it could also be an O2 sensor or mass airflow sensor. If your O2 or MAF sensors have more then 100,000 miles on them, replace all three. For the O2, ONLY use an OEM part (you can buy new Denso sensors on Amazon, around $40).