DTC P1CCC-96: DC/DC Converter Enable Component Internal Failure [08/2023 - ]: Description

WARNING: This page is about a different car, the 2025 Lexus RX 450h+ and 2024 Lexus RX 450h+. However, it is still accessible from the selected car via links, so may be relevant.

The DC/DC converter converts the DC 355.2 V of the HV battery into DC 12 V in order to supply power to areas such as the vehicle lighting system, audio system and various ECUs. Additionally, it charges the auxiliary battery.

A transistor bridge circuit initially converts DC 355 V into alternating current, and a transformer lowers the voltage.

The DC/DC converter controls the output voltage in order to keep a constant voltage at the terminals of the auxiliary battery.

Then, it is rectified and smoothed (into direct current) and converted into DC 12 V.

The hybrid vehicle control ECU sends a signal to the DC/DC converter to prohibit its control and receives signals indicating a normal or abnormal condition of the 12 V charging system via the NODD signal line.

If the DC/DC converter malfunctions, the vehicle will become inoperative. Therefore, the hybrid vehicle control ECU monitors the operation of the DC/DC converter and detects malfunctions.

This DTC is stored when the DC/DC converter circuit has a malfunction or its operation is prohibited by a fail-safe function, or the auxiliary battery voltage drops to 11 V or less with the ignition switch to ON (READY).

If a DC/DC converter malfunction occurs, DC/DC converter malfunction signals are sent from the DC/DC converter to the hybrid vehicle control ECU via the NODD signal line.

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	DTC Output from	Priority	Note
P1CCC-96	DC/DC Converter Enable Component Internal Failure	Both of the following conditions are met: The DC/DC converter is malfunctioning and the auxiliary battery voltage is 11 V or less.* The DC/DC converter is malfunction for 5 seconds. (1 trip detection logic)	No. 1 luggage room relay block and No. 1 junction block assembly Hybrid vehicle control ECU DC/DC converter cooling system Cooling fan system DC/DC converter assembly No. 1 junction block assembly DC/DC fuse Floor under wire No. 2 HV floor under wire	Does not come on	Master Warning: Comes on	Hybrid Control	A	SAE Code: P1CCC

HINT:

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