Circuit Description: Notes

This diagnostic monitors the manifold absolute pressure (MAP) sensor response to pressure changes in the intake manifold. The pressure changes occur based on engine load and the throttle valve opening. The MAP sensor has the following circuits:

• A 5-volt reference circuit
• A low reference circuit
• A signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The PCM receives a low voltage on the signal circuit when manifold vacuum is high at idle or deceleration. The PCM receives a high voltage when manifold vacuum is low at wide open throttle (WOT) or when the ignition is ON and the engine is OFF. If the PCM detects a MAP sensor signal for voltage that is less than a predetermined value, this DTC sets.

The following table illustrates the difference between MAP kPa, signal voltage, and engine vacuum.