P1153 - FAULT CODE - OBD2

P1153 BMW, BUICK, CADILLAC, CHEVROLET, GMC, PONTIAC, SATURN: HO2S INSUFFICIENT SWITCHING BANK 2 SENSOR 1

Engine control systems rely heavily on inputs provided by sensors that help regulate the engine performance, emissions, and other key engine performance factors. One of these sensors is the HO2S (Oxygen Sensor or O2 Sensor), which is installed in the exhaust manifold. It controls the unburned oxygen in the exhaust once it comes out from the engine. It also monitors oxygen levels to measure the fuel mixture to make it as optimal as possible.

Many factors can affect whether the fuel mixture is rich or lean. Among these factors, we have air temperature, engine coolant temperature, barometric pressure, airflow, engine load, and even throttle position. Although other sensors monitor these factors, the O2 sensor is the key to measure the fuel mixture.

The PCM (Powertrain Control Module) monitors O2 Sensor activity. During 100 seconds of monitoring, the control module expects to see changes in the oxygen sensor from rich to lean and vice versa, and each one of these changes is counted. The sensor is determined to change from lean to rich when the voltage is less than 300 mV and goes to 600 mV. If the sensor has a voltage of 600 mV and drops to 300 mV, it is considered rich. If the PCM determines that the O2 Sensor does not change enough, the P1153 OBDII fault code will be set.

• Check Engine lamp ON.
• Irregular motor operation.

The factors that lead to the setting of the P1153 OBD2 diagnostic code are:

• Fuel pressure may not be enough.
• The engine may be leaking vacuum.
• HO2S 1 cables or connectors may have deficiencies.
• The oxygen sensor may be defective.
• There may be a bad fuel injector.

To solve the DTC P1153 OBDII code, try this:

• See Technical Service Bulletins.
• Check with a scanner if additional DTCs to P1153 are set. If so, perform the diagnosis of these codes following the order shown in the tool.
• With the engine running and at operating temperature, use the scanner to monitor the oxygen sensor voltage. If you find a voltage below the specified voltage, it is necessary to check the high signal voltage and the condition of the connector. If you discover inconsistencies, make the appropriate corrections.
• Check the O2 Sensor wiring for common deficiencies due to wear or burns. If inconsistencies are found in these components, the sensor may be in poor condition. Adjust if necessary.