The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, intake air temperature (IAT), and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation the greatest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is on while the engine is off. Under these conditions, the ECM uses the MAP sensor to determine the current BARO. The least manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 12 kPa, when pressures are less, to as great as 103 kPa, depending on the current BARO. The ECM monitors the MAP sensor signal for pressure outside of the normal range.

P0107

P0108

P0107

The ECM detects that the MAP sensor voltage is less than 0.10 volt for more than 4 seconds.

P0108

The ECM detects that the MAP sensor voltage is more than 4.90 volts for more than 4 seconds.

DTCs P0107 and P0108 are Type B DTCs.

DTCs P0107 and P0108 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

Scan Tool Reference

Special Tools Required

1. If P0641 or P0651 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
2. Ignition OFF for 90 seconds, determine the current vehicle testing altitude. Ignition ON, observe the scan tool BARO parameter. Compare the parameter to the Altitude Versus Barometric Pressure table. The BARO parameter should be within the specified range as indicated in the table.
3. Use the scan tool and compare the MAP Sensor parameter to a known good vehicle, under various operating conditions.
4. Ignition ON, observe the scan tool MAP sensor parameter. Start the engine. The MAP Sensor parameter should change.

⇒	Operate the vehicle within the Conditions fro Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the MAP harness connector at the MAP sensor.
2. Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal A and ground.

⇒	If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground.

⇒	If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

⇒	If greater than 5.2 volts test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Verify the scan tool MAP Sensor parameter is less than 12 kPa.

⇒	If greater than 12 kPa, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

5. Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit terminal C. Verify the scan tool MAP Sensor parameter is greater than 103 kPa.

⇒	If less than 103 kPa, test the signal circuit terminal B for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

6. If all circuits test normal, test or replace the MAP sensor.

Important: You must perform the circuit/system testing, in order to verify the integrity of the MAP sensor circuits, before proceeding with the component testing.

Erratic Signal Test

1. Ignition OFF, remove the MAP sensor.
2. Install a 3A fused jumper wire between the 5-volt reference circuit terminal C and the corresponding terminal of the MAP sensor.
3. Install a jumper wire between the low reference circuit terminal A of the MAP sensor and ground.
4. Install a jumper wire at terminal B of the MAP sensor.
5. Connect a DMM between the jumper wire from terminal B of the MAP sensor and ground.
6. Ignition ON, with the J 23738-A or J 35555 , slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 0-5.2 volts without any spikes or dropouts.

⇒	If the voltage reading is erratic, replace the MAP sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.