P1161 - FAULT CODE - OBD2

P1161 BUICK, CADILLAC, CHEVROLET, GMC: HO2S HEATER CONTROL CIRCUIT BANK 2 SENSOR 2

HO2S (Oxygen Sensors) are key parts of engine management. Their function is to monitor the oxygen activity in the exhaust and then provide a voltage signal to the PCM (Powertrain Control Module). Once this data is received, the controller adjusts the air/fuel mixture parameters as necessary.

An important factor for HO2S to provide accurate readings is its temperature. It is for this reason that they have a heating element, whose objective is to achieve this operating temperature in the shortest time

The PCM continuously checks the system, including the oxygen sensors, to verify that their performance is adequate. P1161 OBDII fault code indicates that the HO2S heater control circuit number 2 on bank 2 has failed.

• Check Engine light on.
• Reduced fuel economy.
• Irregular engine operation.

The reasons why the P1161 OBD2 diagnostic code is set are:

• HO2S 2 wires or connectors may be deficient.
• The Oxygen Sensor 2 heater circuit may be malfunctioning due to bad electrical connections.
• The Oxygen Sensor may be defective.

The steps to follow to correct the DTC P1161 OBDII code are as follows:

• To start the diagnosis, consult the Technical Service Bulletins.
• With a scanner check if there are other fault codes stored, especially those that refer to fuel injection system problems or failures with the HO2S. The diagnosis of these should follow the order shown on the tool.
• Verify that the wires and connectors of the number 2 Oxygen Sensor on bank 2 have no damage caused by wear, burns, or corrosion. Performs repairs as required.
• Monitors the HO2S 2 parameters using a scanner. In this check, take into account that the engine must be at operating temperature. Compare the values obtained with the specified values and if discrepancies are found, check the integrity of the electrical connections or the sensor itself.