P0107

DTC P0107 MAP Sensor Circuit Low Voltage (1 Of 2):

DTC P0107 MAP Sensor Circuit Low Voltage (2 Of 2):

MAP System:

CIRCUIT DESCRIPTION
The Manifold Absolute Pressure (MAP) sensor responds to changes in 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 Vehicle Control Module (VCM) on the MAP signal circuit. This voltage signal varies from 1.0-1.5 volts at closed throttle to 4.04.6 volts at wide open throttle (low vacuum). The VCM utilizes the MAP signal and throttle position in order to determine the correct amount of fuel delivered to the engine. This DTC is a type A DTC.

CONDITIONS FOR SETTING THE DTC

^ No Throttle Position (TP) sensor DTCs.
^ Engine operating.
^ Throttle Position is at least 0% when engine speed is no more than 800 RPM.
^ Throttle Position is at least 12.5% when engine speed is greater than 800 RPM.
^ MAP voltage less than 0.05 volts.

ACTION TAKEN WHEN THE DTC SETS
The VCM turns on the Malfunction Indicator Lamp (MIL) when the DTC P0107 is reported and 1 failure has occurred. The VCM substitutes a calculated value for the MAP sensor value so acceptable performance is maintained

CONDITIONS FOR CLEARING THE MIL/DTC
The VCM turns the MIL off 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 (coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

DIAGNOSTIC AIDS
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 Intermittents.

Important: The electrical connector must remain securely fastened.

Important: Disconnect the sensor from the bracket and twist the sensor by hand (only) in order to check for intermittent connections. The output changes greater than 0.1 volt indicates a bad connector or connection. If OK, replace the sensor.

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

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

2. This step determines if DTC P0107 is the result of a hard failure or an intermittent condition.
3. By jumping the 5 volt reference to the signal circuit, this step determines if the sensor is at fault, or if there is a problem with the VCM or 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 signal circuit are OK.
10. The VCM terminals GR 12 and GR 27 are spliced together inside the VCM. When checking the 5 volt reference for a short to ground, both the 5 volt reference circuits and all the components on the 5 volt reference circuits must also be checked.