DTC C1746: Gate Solenoid Valve Circuit Malfunction [08/2019 - ]: Description

The suspension control ECU opens the gate solenoid valve (No. 2 height control valve) to lead the compressed air to the height control cylinder (pneumatic cylinder) and to raise the vehicle height.

Further, the gate solenoid valve (No. 2 height control valve) opens and closes the passage between the right and left height control cylinders (pneumatic cylinders).

The No. 2 height control valve consists of a leveling solenoid valve and a gate solenoid valve.

The gate solenoid valve opens and closes the passage between the compressor and the height control cylinder (pneumatic cylinder).

DTC Code	Detection Condition	Trouble Area
C1746	When either of the following is detected: With the height control valve inactivated, an open signal of the height control valve is detected for 1 second or more. With the height control valve activated, a short signal of the valve is detected 8 times successively.	Wire harness or connector Gate solenoid valve (No. 2 height control valve) Suspension control ECU

HINT:

Once the ECU stores DTC C1746 in the memory, the vehicle height control is suspended until a normal signal is input to the ECU from the height control solenoid valves. However, control is resumed if the engine switch is turned off, then on (IG) again.
Malfunction in the gate solenoid valve:
The height control operation is suspended, and the height control indicator light does not change by operating the height control switch.