The generic OBDII code of P0068 has to do with the Manifold Absolute Pressure (MAP) sensor and how it’s communicating with your Ford PCM. Typically this means that the MAP sensor sees a value that is well outside the range that the ECU is expecting, and today we’ll be showing you how to service a Ford Fiesta MAP sensor in a 2014 Ford Fiesta ST with the 1.6 liter turbocharged engine in it.
DTC P0068 or MAP/MAF – Throttle Position Correlation Error as it’s called, is caused when your ECU sees a disparity between the amount of air the MAP sensor is reporting, and how much should be entering the motor based on throttle position. The manifold absolute pressure sensor in your Ford is basically a thin wire element that measures the air entering the intake manifold.
This Ford MAP sensor is powered to a predetermined value by the ECU, and the sensor works based on this value. As you depress the gas pedal and more air volume increases it requires more voltage to maintain the temperature. The less air that enters the motor, the less voltage it requires to maintain itself.
Your Ford ECU uses this value along with the throttle position sensor to operate and run the engine. Accurate and correct readings will assist your Ford Fiesta in achieving the target 14.5:1 air / fuel ratio it’s aiming for. When your Ford ECU cannot do this for whatever reason, and one or more of the sensors is reporting a disparity, your Malfunction Indicator Lamp sets the P0068 trouble code.
This Ford Fiesta ST MAP sensor part number is AG9Z-9F479-A and it’s a three pin MAP sensor that’s mounted to the intake plenum. For all non turbo Duratec Fiestas the manifold absolute pressure (MAP) sensor is part of the intake pipe.
To begin our how to service a Ford Fiesta MAP sensor DIY guide, you’ll need to disconnect the negative terminal on your battery. Doing this will prevent the chance of any freak accident occurring that could damage your fuses, wiring or ECU.
Remove the upper engine cover by grabbing the top and bottom of the Ford Fiesta cover and pulling down and out. Once the cover has been popped off the circular mounting balls, you can access the engine and MAP sensor.
Your Ford Fiesta MAP sensor is mounted to the intake manifold to the left of your engine bay.
This MAP sensor is connected by a three pin weatherproof connector that we’ll be going over shortly when it comes time for testing your MAP circuit. If you are replacing your unit, remove the safety hex screw shown above to free your MAP sensor.
In order to test your Ford Fiesta MAP sensor, you’ll need a multimeter or voltmeter. Not sure what that is? Check out our handy guide on using a multimeter to test your automotive circuits.
Connect the black lead to the negative terminal on your battery, and then probe PIN C, which should have 5 volts of switched power. If you have a power circuit at the C pin, move onto PIN B which should be the low reference ground signal. So long as you have power and ground at these two terminals, your MAP sensor should be operating correctly.
With your new MAP sensor now installed, you now know how to service a Ford Fiesta MAP sensor. If you have any questions about this DIY article, or any questions regarding P0068, please leave them below!