DTC P19E1-00: DC/DC Converter System Performance [11/2022 - ]: Description

WARNING: This page is about a different car, the 2025 Toyota Corolla Cross, 2024 Toyota Corolla Cross, and 2023 Toyota Corolla Cross. However, it is still accessible from the selected car via links, so may be relevant.

The DC/DC converter converts the voltage from the HV battery to supply power to the vehicle lights, audio system and various ECUs, etc.

At the same time, it performs charging of the auxiliary battery, controlling the output voltage to maintain a specific voltage at the auxiliary battery terminal.

Via CAN communication, the hybrid vehicle control ECU sends stop commands to the DC/DC converter, and receives DC/DC converter Normal/Malfunction status signals.

When an auxiliary charging system malfunction causes DC/DC converter output to stop, and either the auxiliary battery voltage is 11 V or more for 5 seconds or more, or the auxiliary battery voltage is 11 V or less for 0.05 seconds or more, this DTC is stored.

This DTC may also be stored if a malfunction of the inverter cooling system (blockage, inverter water pump malfunction, etc.) or a high-voltage insulation malfunction occurs.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Warning Indicate	Note
P19E1-00	DC/DC Converter System Performance	Any of the following conditions are met: DC/DC converter stop signal is ON, and auxiliary battery voltage is 11 V or more for 5 seconds or more* DC/DC converter stop signal is ON, and auxiliary battery voltage is 11 V or less for 0.05 seconds or more* (1 trip detection logic)	Hybrid vehicle control ECU Inverter with converter assembly Hybrid vehicle transaxle assembly Inverter cooling system Cooling fan system Wire harness or connector DC/DC fuse PCU NO. 2 fuse	Does not come on	Master Warning: Comes on	SAE Code: P19E1

HINT:

*: If the DC/DC converter is malfunctioning, its operation and charging will be stopped and the auxiliary battery voltage will drop.