DTC C1020-00: Ignition Switch On/Start Position Malfunction [11/2021 - ]: Description

WARNING: This page is about a different car, the 2025 Lexus NX 350h, 2024 Lexus NX 350h, 2023 Lexus NX 350h, and 2022 Lexus NX 350h. However, it is still accessible from the selected car via links, so may be relevant.

Refer to DTC C110E-14.

Refer to DTC C110E-14: Brake Booster Motor "A" Supply Voltage Circuit Short to Ground or Open [11/2021 - ]

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	DTC Output from	Note
C1020-00	Ignition Switch On/Start Position Malfunction	When the IG1 terminal voltage is less than 2.8 V, the IG2 terminal voltage is 10.2 V or more for 4 seconds or more.	Open or short in IG1 circuit Improperly connected connector, deformation or corrosion of terminals No. 1 skid control ECU (brake booster with master cylinder assembly)	Comes on	Brake/EPB	SAE Code: C1021 (Case 2 and 3) Output ECU: Both skid control ECUs