Re: GMC Denali XL. "Service Engine Soon" light goes on. My son checked it and it it reads on his gadget: Heater Bank Sensor 1 Bank 1. How important is this to have this fixed. Right away, no rush? How much?

Hi, the pre-converter oxygen sensors have a heater circuit that warms the sensor during a cold start up. The PCM supplies 12volts to the sensor for about 15 seconds to the heater element in the
sensor, this heating of the sensor helps it to read more accurate when cold witch will increase the effiency of your vehicle. When the PCM detects that the sensor is not heating up it will set the code for the heater circuit performance. The most common problem is the sensor but could be a supply problem, you should check the brown wire on the sensor connector for 12 volts but will only be supplied after you first cut the key on when cold. This is not a critical failure so there is no rush to repair, but it should be eventually.

No rush at all, your car on board computer is programmed to remind the end user that your car needs servicing very soon depend on the mileage you covered unsually every 5,000 km..pls. refer to your service manual what interval service your car needs at the moment...