DESCRIPTION
INSPECTION PROCEDURE
INSPECT FOR FLUID LEAK
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (LEVELING VALVE, ACCUMULATOR VALVE AND GATE VALVE)
INSPECT SUSPENSION CONTROL RELAY (AHC)
CHECK HEIGHT CONTROL PUMP AND MOTOR
INSPECT FLUID LINE
DTC C1766 Height Control Pump Motor Current
DESCRIPTION
In case that the height control has not finished in spite of performing the raise control for a certain period of time, the ECU interrupts the height control.
| DTC Code | Detection Condition | Trouble Area |
| C1766 | When the height control pump and motor operates continuously for 135 seconds. | Fluid leakage
No. 1 height control valve
Suspension control relay
Height control pump and motor
Clog in the fluid line
Suspension control ECU
|
INSPECTION PROCEDURE
If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed ().
When the cargo weight is extremely heavy, this DTC may be stored.
Inspect for fluid leaks ().
| | REPAIR FLUID LEAK OR REPLACE LEAKING PART(S) |
|
|
| 2.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (LEVELING VALVE, ACCUMULATOR VALVE AND GATE VALVE) |
Connect the intelligent tester to the DLC3.
Start the engine and turn the tester on.
Select the Active Test mode on the intelligent tester.
Check the operation of the leveling valve solenoid, accumulator valve solenoid and gate valve solenoid when operating the solenoid with the intelligent tester.
AHC| Tester Display | Test Part | Control Range | Diagnostic Note |
| Front Right Height Solenoid | Front height control solenoid valve RH | ON or OFF | Operation of solenoid can be heard. |
| Front Left Height Solenoid | Front height control solenoid valve LH | ON or OFF | Operation of solenoid can be heard. |
| Rear Right Height Solenoid | Rear height control solenoid valve RH | ON or OFF | Operation of solenoid can be heard. |
| Rear Left Height Solenoid | Rear height control solenoid valve LH | ON or OFF | Operation of solenoid can be heard. |
| Accumulator Valve | Accumulator solenoid valve | ON or OFF | Operation of solenoid can be heard. |
| Front Gate Valve | Front gate solenoid valve | ON or OFF | When the Front Gate Valve item of the Active Test is operated, the Front Gate Valve item of the Data List changes to ON/OFF. |
| Rear Gate Valve | Rear gate solenoid valve | ON or OFF | When the Rear Gate Valve item of the Active Test is operated, the Rear Gate Valve item of the Data List changes to ON/OFF. |
- OK:
- The leveling valve solenoid, accumulator valve solenoid and/or gate valve solenoid operates.
| | REPLACE NO. 1 HEIGHT CONTROL VALVE ()
|
|
|
| 3.INSPECT SUSPENSION CONTROL RELAY (AHC) |
Remove the suspension control relay from the engine room relay block.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| 3 - 5 | Battery voltage is not applied to terminal 1 and 2 | 10 kΩ or higher |
| Battery voltage is applied to terminal 1 and 2 | Below 1 Ω |
| | REPLACE SUSPENSION CONTROL RELAY |
|
|
| 4.CHECK HEIGHT CONTROL PUMP AND MOTOR |
Remove the height control pump and motor ().
Inspect if the compressor is stuck.
Apply battery voltage to the compressor motor and check the operation of the motor.
- OK:
| Measurement Condition | Specified Condition |
Battery positive (+) → Terminal 2
Battery negative (-) → Terminal 1 | Motor operates |
Do not allow the motor to operate for 60 seconds or more.
If the height control pump and motor is shorted, locked, or has a similar type of malfunction, a large amount of current will be flowing. Therefore, if the motor does not operate, immediately stop this inspection.
| | REPLACE HEIGHT CONTROL PUMP AND MOTOR ()
|
|
|
Check if the fluid line is clogged.
Check if the fluid line that connects the height control pump and motor and No. 1 height control valve is clogged. If it is not clogged, there probably is foreign matter clogging the interior of the No. 1 height control valve.
Follow the removal and installation procedures for each part, as all parts need to be removed.
| | REPAIR OR REPLACE CLOGGED PARTS |
|
|
| OK | |
| |
| REPLACE SUSPENSION CONTROL ECU ()
|
|
