E031

Code E031:

Sensor Circuit:

The Manifold Absolute Pressure (MAP) sensor, is a sensor that changes resistance based upon manifold vacuum. The PCM/ECM provides a 5 volt reference and ground. The MAP signal varies between ground and 5 volts as manifold vacuum varies. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum). The PCM/ECM uses MAP sensor values as an indicator of engine load. Code E031 sets when the PCM/ECM detects a MAP sensor signal that is too high. The MAP sensor connector is located on the rear top of engine.

TEST CONDITIONS:

Tested continuously.

FAILURE CONDITIONS:

MAP value greater than 108 kPa for at least .2 seconds.

ACTION TAKEN:

1. PCM/ECM turns on "SERVICE ENGINE SOON" telltale.
2. PCM/ECM sets BARO value equal to 92.2 kPa.
3. PCM/ECM uses a substitute MAP value based on engine speed and throttle switch status.


NOTES ON FAULT TREE:

1. If PCM/ECM parameter ED02 goes to 14 to 16 kPa with the sensor unplugged, the fault is at the MAP sensor or sensor connector.

2. Checking for an open circuit from Pin A of the sensor connector to PCM/ECM Pin A5 (ground). If the ground is open, the signal voltage will always be high.

NOTE ON INTERMITTENTS:

Manipulate MAP sensor connector, MAP wiring, and PCM/ECM connector while observing PCM/ECM parameter ED02. Apply and release vacuum to the MAP sensor vacuum port using a vacuum source. If the PCM/ECM parameter ED02 displays greater than 108 kPa, the condition has been induced and the cause of the intermittent should be repaired. If wiring and connectors check out OK, substitute a known good MAP sensor and retest.