The Manifold Absolute Pressure (MAP) sensor responds to changes in the intake manifold pressure (vacuum). A 5 volt reference is applied to the sensor. A variable resistor moves in relation to manifold pressure and a voltage signal is sent back to the ECU on the 5 volt reference circuit. This voltage signal varies from 1.0-1.5 volts at closed throttle (high vacuum) to 4.0-4.5 volts at wide open throttle (low vacuum).

A substantial change in throttle position and engine speed must precede any substantial change in MAP. If a substantial change in throttle position and engine speeds has occurred and a change in MAP did not occur, than a MAP malfunction has occurred.

This is a type B DTC.

The following conditions will set the DTC:

A fault is detected if a TP sensor change of greater than 20% is detected while at the same time the corresponding MAP change is less than 6 kPa (1.77 in. mercury).

The ECU sets the DTC 32 after 2 consecutive driving trips with the fault active.

The ECU turns the MIL OFF after 3 consecutive driving trips without a fault condition present. A DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 40°C (72°F) from the start-up coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during that same ignition cycle) or the code clearing procedure has been used.

Always diagnose ANY VCM codes that are present before beginning this diagnostic procedure.

Check the MAP sensor vacuum source for leaks, restrictions or faulty connections.

Check the MAP sensor output voltage to the ECU. This voltage represents a barometric reading to the ECU when the engine is not running.

The number(s) below refer to the step number(s) on the diagnostic table.

Important: When comparing the readings from a known good vehicle, compare vehicles which use a MAP sensor having the same color insert or the same Hot Stamped number.

4. Applying 34 kPa (10 Hg) of vacuum to the MAP sensor should cause the voltage to change. The voltage value obtained from subtracting the second reading from the first should be greater than 1.5 volts. When applying vacuum to the sensor, the change should be instantaneous. A slow voltage change indicates a faulty sensor.

   Important: The electrical connector must remain securely fastened.

   Important: Replace the MAP sensor-to-intake manifold seal after removing the MAP sensor from the intake manifold.

5. Disconnect the sensor from the bracket. Gently twist the sensor in order to check for intermittent connections. Output changes greater than 0.1 volt indicate a bad connector or connection. If the connector is OK, replace the sensor.