Code 21
Problem with O2 Sensor feedback circuit. Occurs if engine temperature is above 170°F (77°C), engine speed is above 1500 RPM, but to O2 sensor signal for more than 5 seconds.
Problem with O2 Sensor feedback circuit. Occurs if engine temperature is above 170°F (77°C), engine speed is above 1500 RPM, but to O2 sensor signal for more than 5 seconds.