Manifold Pressure/Vacuum Sensor: Testing and Inspection

NOTE:
To perform a complete test of Manifold Absolute Pressure (MAP) sensor and its circuitry, refer to appropriate Powertrain Diagnostic Chart. To test the MAP sensor only, refer to the following:


PROCEDURE

Throttle Body:

1. Inspect the rubber nipple (fitting) from the MAP sensor to the throttle body. Repair as necessary.

CAUTION: When testing the MAP sensor, be sure that the harness wires are not damaged by the test meter probes.

MAP Sensor Connector Terminals Typical:

2. Test the MAP sensor output voltage at the MAP sensor connector between terminal A and terminal B.

^ With the ignition switch ON, and the engine OFF, output voltage should be 4-to-5 volts. The voltage should drop to 1.5-to-2.1 volts with a hot, neutral idle speed condition.

3. Test Powertrain Control Module (PCM) (terminal/pin-1) for the same voltage described above to verify the wire harness condition. Repair as necessary.

4. Test MAP sensor supply voltage at sensor connector between terminal A and terminal C with the ignition ON.

^ The voltage should be approximately 5 volts (±O.5V). Five volts (±0.5V) should also be at terminal 6 of the PCM wire harness connector. Repair or replace the wire harness as necessary.

5. Test the MAP sensor ground circuit at sensor connector terminal A and PCM connector terminal/pin-4. Repair the wire harness if necessary.

6. Test the MAP sensor ground circuit at the PCM connector between terminal/pin-4 and terminal/pin-11 with an ohmmeter.

^ If the ohmmeter indicates an open circuit, inspect for a defective sensor ground connection. If the ground connection is good, replace the PCM. If terminal/pin-4. has a short circuit to 12 volts +, correct this condition before replacing the PCM.