P1150 - FAULT CODE - OBD2

P1150 FORD, LINCOLN, MERCURY: LACK OF UPSTREAM HEATED OXYGEN SENSOR SWITCH ADAPTIVE FUEL LIMIT BANK 2

The right functioning of the HO2S (Oxygen Sensor) is checked through a strategy called Oxygen Sensor monitoring. Fuel control is adjusted under certain conditions so that the output voltage and the time it takes for the upstream Oxygen Sensor to change from lean to rich and vice versa (known as response rate) can be the most appropriate. The downstream HO2S is used by the Catalyst Monitor to determine and regulate the output voltages so that they are also correct.

The Oxygen Sensor monitor is enabled only when the MAF (Mass Air Flow), ECT (Engine Coolant Temperature), CKP (Crankshaft Position), and TPS (Throttle Position) inputs are obtained. Also, the fuel system and ignition system troubleshooting monitor tests need to be completed. Once these requirements are fulfilled, it is verified how wide the upstream sensor signal voltage is, and the response rate of the upstream sensor. If the voltage obtained differs with a calibrated maximum voltage, or if the oxygen sensor shows after such tests any slope, the system itself tries to make the appropriate adjustments.

DTC P1150 OBDII is set by the Powertrain Control Module (PCM) when the PCM fails to control the fuel trim due to an excessively rich or lean condition.

• Check Engine lamp ON.
• Irregular motor operation.

The P1150 OBD2 diagnostic code is set for one of the following reasons:

• The fuel pressure may not be suitable.
• There could be vacuum leaks in the motor.
• An HO2S from bank 2 may be in poor condition.
• Possibly a fuel injector is defective.
• The fuel pressure regulator may be damaged.
• The MAF sensor may have contamination levels.

To solve the P1150 OBDII fault code, try this:

• First, consult the Technical Service Bulletins.
• With a scan tool, check if other DTCs in addition to P1150 are set, looking more closely for those that point to problems with the exhaust system or an Oxygen Sensor.
• Check that there is no damage to the wiring or connectors of the Oxygen Sensor on bank 2. If common deficiencies are found, make the necessary repairs.
• Measure the fuel pressure. Check if this value is within the parameters indicated by the manufacturer. If the pressure obtained is not outside the required levels, check the pressure regulator and injectors for damage. Make the necessary corrections.
• Inspect all the intake hoses, as well as manifold connections. Look for poor connections or damage to the hoses. If such conditions are found, make the appropriate adjustments.