Advanced Diagnostics

DTC P1549: Charging System High Voltage




General Description
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 battery battery's state of charge, the electrical load, and engine rpm.

When the IGP (power source) terminal voltage is a set value or less and this condition continues for a set time, the PCM detects a malfunction and a DTC is stored.




Monitor Execution, Sequence, Duration, DTC Type, OBD Status




Enable Conditions

Malfunction Threshold
The IGP terminal voltage is 16.0 V or more for at least 60 seconds.

Diagnosis Details

Conditions for illuminating the indicator
When a malfunction is detected, the DTC and the freeze frame data are stored in the PCM memory. The MIL does not come on.

Conditions for clearing the DTC
The DTC and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.