C1744

SUSPENSION CONTROL: AIR SUSPENSION SYSTEM: C1743,C1744: Rear Height Control Solenoid Valve RH Circuit Malfunction


DESCRIPTION

The rear height control valve independently opens and closes paths to the pneumatic cylinder for the rear wheel side by receiving signals from the suspension control ECU.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
- Before performing troubleshooting, inspect the connectors of related circuits.
- If DTC C1782 (Power Source Voltage Malfunction) is output at the same time, perform troubleshooting for C1782 first C1782.
- Before replacing the suspension control ECU, perform all of the following again: 1) symptom simulation Electronic Circuit Inspection Procedure; 2) DTC inspection; and 3) the Techstream inspection (Data List or Active Test). If no malfunctions are found in other areas, replace the suspension control ECU.
- If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed Programming and Relearning.

PROCEDURE

1. CLEAR DTC

(a) Clear the DTC Air Suspension System.

NEXT -- Continue to next step.

2. CHECK HEIGHT CONTROL SOLENOID VALVE OPERATION (ACTIVE TEST)

(a) Turn the power switch OFF.

(b) Connect the Techstream to the DLC3.

(c) Turn the power switch ON (IG) and the Techstream ON.

(d) Enter the following menus: Chassis / Air suspension / Active Test.

(e) Check the operation sound of the height control solenoid valve when the solenoid is turned on through the ACTIVE TEST.

Air Suspension





OK:

An operation sound is heard 1 second after the height control solenoid valve is turned on.

NG -- INSPECT REAR HEIGHT CONTROL VALVE

OK -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

3. INSPECT REAR HEIGHT CONTROL VALVE

(a) Remove the rear height control valve Removal.





(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:

C1743:





C1744:





NG -- REPLACE REAR HEIGHT CONTROL VALVE Removal
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (REAR HEIGHT CONTROL VALVE - ECU AND BODY GROUND)

(a) Disconnect the L88 ECU connector.

(b) Disconnect the z14 height control valve connector.

(c) Measure the resistance according to the value(s) in the table below.





Standard resistance:

C1743:





C1744:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE SUSPENSION CONTROL ECU Removal