Alternator harness is open or shorted
Alternator circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
The alternator is driven by the engine and generates electricity to supply the necessary power to the electrical system and to charge the battery. The alternator voltage target values of 14.5 V and 12.5 V are achieved by switching the alternator control mode (controlled by the Powertrain Control Module (PCM)). The alternator output signal is sent to the PCM, and it varies according to the batteryís state of charge, the electrical load, and the engine speed.
When the engine speed is a specified value and the IGP terminal voltage is below a set value when the alternator is in the 14.5 V mode, and the alternator power generation amount is within the set range and this condition continues more than a set time, the PCM detects a malfunction and a Diagnostic Trouble Code (DTC) is stored.