DTC C1752: Height Control Compressor Motor Circuit Malfunction [08/2019 - ]: Description

When the "UP" side of the height control switch is pressed, a signal is sent from terminal RC of the suspension control ECU to switch the AIR SUS relay ON. As a result, the relay contacts close and the compressor motor turns on, producing compressed air.

The suspension control ECU detects the amount of current flow to the compressor motor by means of the differences in potential at terminals RM+ and RM- of the suspension control ECU. In this way, the suspension control ECU monitors the compressor circuit for abnormalities.

DTC Code	Detection Condition	Trouble Area
C1752	When either of the following is detected: When the power supply voltage is at 12 V or higher, a lock signal of the height control compressor motor is detected for 4 seconds while the AIR SUS relay is activated. When the power supply voltage is at below 12 V, a lock signal of the height control compressor motor is detected for 8 seconds while the AIR SUS relay is activated.	Wire harness or connector No. 1 height control compressor Suspension control ECU

HINT:

Once the ECU stores DTC C1752 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.