The Manifold Absolute Pressure (MAP) sensor responds to changes in the intake manifold pressure (vacuum). A 5 volt reference is applied to the sensor on the 5 volt reference circuit. A variable resistor moves in relation to the manifold pressure and a voltage signal is sent back to the VCM on the MAP sensor signal circuit. This voltage signal will vary from 1.0-1.5 volts at closed throttle to 4.0-4.6 volts at wide open throttle (low vacuum). The VCM utilizes the MAP signal and the throttle position in order to determine the correct amount of fuel delivered to the engine. This DTC is a type D DTC.

The following conditions will set the DTC:

1. No TP sensor DTCs
2. The engine is running
3. The TP is at least 0% when engine speed is no more than 1000 RPM (800 RPM for 7.4L)
4. Or the TP is at least 10.1% (12.5% for 7.4L) when the engine speed is greater than 1000 RPM (800 RPM for 7.4L)
5. The MAP voltage less than 0.25 volts (0.20 volts for 7.4L)

The VCM turns the MIL ON when this DTC is reported and 1 failure has occurred. The VCM substitutes a calculated value for the MAP sensor value so that acceptable performance is maintained.

The VCM turns OFF the MIL after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle) or the scan tool clearing feature has been used.

An intermittent open in the MAP sensor signal circuit or the 5 volt reference circuit will result in a DTC P1107.

With the ignition ON and the engine OFF, the manifold pressure is equal to the atmospheric pressure with the signal voltage high. The VCM uses this information as an indication of the altitude of the vehicle.

Comparison of this reading with a known good vehicle using the same sensor is a good way to check the accuracy of a suspect sensor. Readings should be the same ±0.4 volt.

Refer to Intermittent Conditions .

Important: The electrical connector must remain securely fastened.

Important: After removing the MAP sensor from the intake manifold, replace the MAP Sensor to intake manifold seal.

Remove the MAP sensor. Twist the sensor by hand (only) in order to check for intermittent connections. Output changes greater than 0.1 volt indicates a bad connector or connection. If OK, replace sensor.

The numbers below refer to the step numbers on the diagnostic table.

2. This step determines if the DTC P1107 is the result of a hard failure or an intermittent condition.

3. Jumpering the 5 volt reference to the signal circuit will determine if sensor is at fault or if there is a problem with the VCM, or the wiring.

4. The scan tool may not display 5 volts. The important thing is that the VCM recognized the voltage as more than 4 volts, indicating that the VCM and MAP sensor signal circuit are OK.