DTC P1450 Or DTC P1451: Condition

WARNING: This page is about a different car, the 2002 Suzuki Esteem. However, it is still accessible from the selected car via links, so may be relevant.

DTC P1450 is set when barometric pressure reading is less than 9.7 in. Hg (33 kPa) or 40 in. Hg (136 kPa) more then specified. Possible cause is ECM (barometric pressure sensor) malfunction.

DTC P1451 is set when difference between barometric pressure reading and intake manifold absolute pressure reading is 7.7 in. Hg (26 kPa) or more. ECM monitors this circuit once per drive cycle. MIL is illuminated when ECM detects malfunction during 2 consecutive drive cycles. Possible causes are:

Manifold Absolute Pressure (MAP) sensor malfunction.
ECM (barometric pressure sensor) malfunction.