Circuit Description
The manifold absolute pressure (MAP) sensor is a potentiometer circuit that varies its resistance as the pressure in the intake manifold changes. The ECM reads a voltage between 0 and 5 volts depending on the resistance value. This value aids in the determination of how far the throttle plate is to be opened, and the duration of fuel injection. The ECM sets this DTC when the voltage signal from the sensor is higher than expected.
DTC Parameters
DTC P0107 will set if MAP voltage is greater than 4.9 volts (90 kPa) when either:
| • | Engine speed less than 1000 rpm, and |
| • | TP sensor less than 70%, and |
| • | No TP sensor DTCs have been set. |
| OR |
| • | Engine speed greater than 1600 rpm, and |
| • | TP sensor greater than 50%, and |
| • | No TP sensor DTCs have been set. |
Important: MAP signal is continuously checked when engine is running.
P0108 is a (type B) DTC.
Diagnostic Aids
To locate an intermittent problem use scan tool to monitor MAP pressure and voltage with engine running.
Wiggling wires while monitoring MAP pressure and voltage may locate area where a short to voltage exists.
With ignition On, Engine Off, the MAP reading should be the same as the barometric pressure reading. Compare it to the reading of a known good vehicle with the same sensor to determine the accuracy of the suspect sensor. Readings should be within 0.40 volts.
Inaccurate readings will occur if resistance measurements are taken on a MAP sensor. The MAP sensor contains an internal amplifier circuit that requires applied voltage to function properly.
