P1151 - FAULT CODE - OBD2

P1151 FORD - LACK OF UPSTREAM HEATED OXYGEN SENSOR SWITCH INDICATES LEAN BANK 2

An integrated strategy known as O2 Sensor Monitoring is used to check that the Oxygen (O2) Sensors are working properly. In some cases, the fuel control or upstream O2 sensors are adjusted so that the output voltage and response rate (switching time from rich to poor or vice versa) are appropriate. Similarly, the downstream O2 sensors are used for Catalyst Monitor. With this data, the output voltages are determined and controlled so that they are as required.

To enable the HO2S monitor, it is necessary to have inputs for coolant temperature (ECT), head temperature, intake air, mass airflow (MAF), throttle position (TPS), and crank position (CKP). Besides, you must complete fuel system monitor and misfire detection monitor tests. Once the HO2S monitor is enabled, the voltage amplitude of the upstream sensor signal is checked, as well as the response of the sensor. To check if the voltage is excessive, it is compared to a calibrated maximum voltage. If an oxygen sensor indicates there is a slope after a test, the system tries to fix it.

The fault code P1151 OBDII is only for Ford vehicles. It is set when the fuel control system does not detect the switching for a certain calibrated time.

• The Check Engine lamp is on.

Reasons to set the diagnostic code P1151 OBD2:

• Fuel pressure may not have the proper levels.
• The engine may have vacuum leaks.
• Bank 2 Oxygen Sensor may be damaged.
• An injector or any fuel pressure regulator may be leaking.
• The MAF Sensor may be dirty or contaminated.

Steps to correct the DTC code P1151 OBDII on your Ford vehicle:

• To start the diagnosis, consult the available TSBs for the model and year. Also, check if there are other codes stored. If so, diagnose those codes, especially if they are related to the exhaust system.
• Check the wiring and circuit connectors of the Oxygen Sensor for Bank 2 for proper condition. If you find any obvious damage, repair it or replace it if necessary.
• Check the manufacturer's specifications for the required fuel pressure values. If this value does not correspond to the requirements, check that the injectors, the regulator, and other components are not in bad condition. Make the necessary corrections.
• Check the intake hoses and manifold seals for inconsistencies that cause vacuum leaks. If this is the case, make the corresponding adjustments.
• Follow the manufacturer's instructions for the O2 Sensor diagnostic steps. If you determine it is defective, replace it.