Possible causes

– Engine Control Module (ECM) outdated or incorrect software
– Faulty Engine Control Module (ECM)

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Engine rough idle
– Engine hesitation

P1109 ACURA Description

The barometric pressure (BARO) sensor is built into the Engine Control Module (ECM) and monitors atmospheric pressure. The ECM estimates appropriate intake airflow from the manifold absolute pressure (MAP) sensor output voltage and BARO sensor output voltage. If the BARO sensor output voltage is a specified value or more, the ECM detects a malfunction and a DTC is stored.