DTC C1020-00: Ignition Switch On/Start Position Malfunction [12/2023 - ]: Description

If a malfunction is detected in the power supply circuit, the No. 1 skid control ECU (brake booster with master cylinder assembly) power source voltage drops, or there is insufficient voltage to operate the main relay, the No. 1 skid control ECU (brake booster with master cylinder assembly) will store these DTCs.

If the auxiliary battery voltage is temporarily low, these DTCs may be stored.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	DTC Output from	Priority	Note
C1020-00	Ignition Switch On/Start Position Malfunction	When the IGR terminal (less than 2.8 V) for 4 seconds or more.	Open or short in IGR circuit Improperly connected connector, deformation or corrosion of terminals No. 1 skid control ECU (brake booster with master cylinder assembly)	Brake Booster	A	Output ECU: No. 1 skid control ECU (brake booster with master cylinder assembly)