ALTITUDE TIMING ADJUSTMENT (B2600I & MPV 2.6L)
The atmospheric pressure sensor monitors atmospheric pressure for the ECU. The voltage signal it sends to the ECU will vary with altitude (about 4 volts at sea level). The ECU will advance ignition timing 6 degrees to compensate for loss of engine power at high altitudes. The high-altitude timing advance is canceled if the ECU test connector is grounded.