B1D78 Code: Meaning, Causes, and Symptoms | OBD2 Codes

B1D78 – Auxiliary Input Circuit Open


B1D78 Possible Symptoms


Engine Light ON (or Service Engine Soon Warning Light)


B1D78 Possible Causes


Faulty Audio Input Jack,Faulty Accessory Protocol Interface Module (APIM),Faulty Audio Control Module (ACM)


B1D78 Description


Audio signals are sent from the Audio Input Jack to the Accessory Protocol Interface Module (APIM). The signals are then sent to the ACM. There are no external power or ground circuits to the audio input jack. The Diagnostic Trouble Code (DTC) sets in continuous memory by the navigation ACM (vehicles without the SYNC??system only) when an open is detected in the audio input jack circuitry for greater than 250 milliseconds.