P0043 - HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 3)

The Oxygen Sensors (HO2S) are pieces used by the motor control module PCM (Power Train Control Module); to determine the oxygen content that is in the exhaust system.

The information obtained from bank 1, Oxygen Sensor 3 (HO2S) is used by the PCM to monitor the performance of the catalyst; an integral part of this sensor is a heater, which is controlled by the PCM to heat the temperature sensor operation, and in this way the motor can enter into a closed loop faster, as well as reduce emissions when starting when it is cold.

The heater circuits are monitored regularly by the PCM, in case there is an abnormal voltage. It is important to know how the heater of your vehicle is controlled because the PCM activates the heater in several circumstances.

• The Check Engine light is on.

A code P0043 may have one or more of the following problems:

• O2 Oxygen sensor in bank 1 may be failing.
• The Oxygen Sensor could be physically damaged.
• Depending on whether it has a control circuit or supply voltage, it may have a short circuit to ground.

To solve the fault code P0043 OBD2 you can review the following components:

• You must make a visual inspection of sensor 3 (O2) in bank 1, or in the wiring system, and check if there is any damage to these components. If you find a defect, you can repair or replace it if necessary.
• Check that the distance between the wiring and the exhaust pipe is considered.
• If you perform the necessary tests and do not find a visual defect, you can unplug the bank 1, the O2 Oxygen Sensor 3 and check if the voltage is 12 volts B +.
• Check that the heating control circuit has no alteration to any damage. If so, you can disconnect the oxygen sensor O2 and with an ohmmeter perform a resistance test of the heating element, if it results in an infinite resistance means that there is an open circuit in the heater.