Chart C1D - Map & BARO Check
NOTE:
The following step numbers refer to the numbers in the accompanying flow chart(s).
- Checks sensor voltage, which is highest when manifold pressure is highest. Output is normally in the middle range for specific altitudes. Low voltage increases spark advance. High voltage decreases spark advance. MAP and BARO sensors are essentially the same device. One measures pressure in manifold and the other measures atmospheric pressure.
- Checks if rate of change of output verses change in pressure is correct. Normal change should be in the middle of the range listed. Voltage should change as soon as vacuum is changed.