The manifold absolute pressure, or simply MAP sensor measures intake manifold pressure. This information is used by the PCM, along with other parameters, to determine engine fuel requirements based on current conditions. The sensor measures ABSOLUTE pressure, not gauge pressure. The absolute pressure at sea level is ~14.7 psi (atmospheric pressure) and gauge pressure at sea level is 0 psi (gauge pressure is equal to absolute pressure - atmospheric). MAP sensors are not known to fail often, but it is common for the MAP sensor line to develop a leak over time.
A poor reading from the MAP sensor can present itself in many ways, typically relating to poor overall performance. The MAP sensor can be tested using a compatible diagnostics tools. To verify correct MAP sensor readings, monitor the manifold absolute pressure and barometric pressure PIDs KOEO (key on, engine off) - the readings should be identical (or very close). If you plan on replacing the sensor, we recommend replacing the hose at the same time.
MAP Sensor Parts List
Description |
Part Number |
MAP sensor |
Motorcraft CX-1961 |
MAP sensor hose |
|
MAP sensor connector |
Ford 3U2Z-14S411-EXC |
How to Replace the MAP Sensor on a 6.0 Power Stroke Diesel
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• Disconnect both negative battery cables.
• The MAP sensor is located on the passenger side; the sensor bracket is mounted to the top of the heater core.
• The sensor itself is affixed to the bracket by (2) T20 Torx screws. It is by far easier to remove the entire bracket than just the sensor. Remove the (3) nuts holding the bracket to the top of the heater core with a 10 mm deep socket.
• With the bracket unbolted, you can easily access the sensor connector and hose. Remove the electrical connector by first sliding the red clip downwards to reveal the locking mechanism, then press and hold the locking tab while pulling the connector off of the MAP sensor.
• Remove the hose from the MAP sensor, then from the intake manifold. Both ends of the hose are secured by simple spring clamps. If you follow the hose from the sensor itself, you'll find the other end is attached to a metal nipple extruding from the intake manifold.
• Remove the sensor from the bracket (2 x T20 Torx), then install the new sensor. The screws are self-tapping, so do not overtighten.
• The replacement hose, Ford part # 4C2Z-9L474-AA, comes much longer than necessary. Use the old hose and sheath as a template to trim the new hose and sheath to the proper length.
• From here, installation is reverse - do not forget to lock the MAP sensor connector by sliding the red clip upwards once it is reconnected.