DTC C1377/43 Capacitor Malfunction: Description

WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.

The brake control power supply (capacitor) is used as auxiliary power for brake control when battery voltage is low.

DTC DETECTION CONDITION

DTC Code	Information Code	DTC Detection Condition	Trouble Area
C1377/43	101	When both conditions below are met IG1 terminal voltage is 9 5 V or more, and malfunction signal (not capacitor communication malfunction) reception condition continues for 3 seconds or more Brake control power supply is deteriorated (indicates a need to replace)	Brake control power supply
↑	102	When both conditions below are met IG1 terminal voltage is 9 5 V or more, and malfunction signal (not capacitor communication malfunction) reception condition continues for 3 seconds or more Self-discharge (current leak) is excessive (internal malfunction)	↑
↑	103	When both conditions below are met IG1 terminal voltage is 9 5 V or more, and malfunction signal (not capacitor communication malfunction) reception condition continues for 3 seconds or more Overvoltage (16 4 V or more) continues to be applied from the battery to the brake control power supply voltage input (+BC) for 10 seconds or more	Positive battery circuit (Apply high voltage)
↑	105	When both conditions below are met IG1 terminal voltage is 9 5 V or more, and malfunction signal (not capacitor communication malfunction) reception condition continues for 3 seconds or more Circuit inside the power back up unit (charge) is malfunctioning	Brake control power supply
↑	106	When both conditions below are met IG1 terminal voltage is 9 5 V or more, and malfunction signal (not capacitor communication malfunction) reception condition continues for 3 seconds or more Circuit inside the power back up unit (back up output circuit) is malfunctioning	↑
↑	108	When both conditions below are met IG1 terminal voltage is 9 5 V or more, and malfunction signal (not capacitor communication malfunction) reception condition continues for 3 seconds or more Circuit inside the power back up unit (voltage monitor circuit) is malfunctioning	↑
↑	109	When both conditions below are met IG1 terminal voltage is 9 5 V or more, and malfunction signal (not capacitor communication malfunction) reception condition continues for 3 seconds or more Open circuit between battery (12 V) and brake control power supply power input (+BC terminal)	ABS MAIN4 fuse Harness or connector
↑	110	When both conditions below are met IG1 terminal voltage is 9 5 V or more, and malfunction signal (not capacitor communication malfunction) reception condition continues for 3 seconds or more When either of the following is detected Open or short circuit between battery (12 V) and brake control power supply output 1 (OUT1) Open or short circuit between battery (12 V) and brake control power supply output 2 (OUT2)	ABS MAIN4 fuse Harness or connector