Note On Intermittents

WARNING: This page is about a different car, the 1989 Cadillac Fleetwood and 1989 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

Manipulate affected wiring and connectors while observing ECM parameter P.0.2. Apply and release vacuum to MAP sensor vacuum part using a vacuum source. If ECM parameter P.0.2 displays greater than 105 kPa, condition has been induced and cause of intermittent should be repaired. If wiring and connectors are okay, substitute a known good MAP sensor and re-test. Code E31 can be set by:

Short to voltage on circuit No. 432.
Open from sensor to ECM on circuit No. 476.
Defective MAP sensor.

Fig 1: Code E31 Schematic - Shorted Map Sensor Circuit

Fig 2: Code E31 Flow Chart- Shorted Map Sensor Circuit