DTC : P15C9: General Description

The powertrain control module (PCM) calculates a vacuum pressure (differential pressure between barometric pressure) in the brake booster based on the brake booster pressure sensor output voltage, and it is used to judge auto idle stop permission. The PCM stores the DTC because of the brake booster pressure sensor malfunction when the value for the brake booster pressure sensor does not fluctuate while repeating the sequence of "vehicle stop"→"vehicle start"→"vehicle stop" for a predetermined number of times (it is a situation that the brake booster pressure value should drop due to the braking operations or should increase/decrease due to the negative pressure being applied from the supply source).