HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
The engine computer is not seeing the correct electrical signal for the heater in the rear oxygen sensor on bank 1. This usually means the heater circuit is open, shorted, or the sensor heater has failed. It can cause poor emissions control and a check engine light.
The vehicle is usually still drivable, but fuel control and emissions monitoring may be affected. Have it repaired soon, especially if the check engine light is flashing or other codes are present.
P0037 sets when the PCM detects a low voltage or low current condition in the heater control circuit for the downstream heated oxygen sensor on bank 1, sensor 2. The heater is used to bring the sensor up to operating temperature quickly so the PCM can monitor catalyst efficiency and control emissions properly. A failure in the sensor heater, wiring, fuse, relay, or PCM driver can trigger this code.
Bank 1 is the side of the engine with cylinder 1. Sensor 2 is the downstream oxygen sensor, located after the catalytic converter.
Usually it causes an emissions problem more than a drivability problem, but fuel economy and emissions can suffer.
No. The code will return if the heater circuit fault is still present.
P0037 refers to the downstream sensor on bank 1, not the upstream sensor.