Last Modified: 4-30-2014 6.6 C Doc ID: RM000001CTQ002X
Model Year: 2006 Model: LX470 Prod Date Range: [05/2005 -           ]
Title: SUSPENSION CONTROL: ACTIVE HEIGHT CONTROL SUSPENSION: C1751/51; Continuous Electric Current to Height Control Compressor; 2006 MY LX470 [05/2005 -        ]

DTC

C1751/51

Continuous Electric Current to Height Control Compressor

DESCRIPTION

In case that the height control has not consisted in spite of performing the raise control for a certain period of time, the ECU interrupts the height control.

DTC No.

DTC Detection Condition

Trouble Area

C1751/51

When the rise control completion condition has not consisted in spite of turning on electricity to the relay for the following period of time

LO → N: 85 seconds

N → HI: 100 seconds
  • AHC pump and motor
  • AHC motor relay
  • Height control sensor link comes off
  • Fluid leakage from the fluid line or each solenoid valve
  • Fluid clog in the fluid line or each solenoid valve
  • Torsion bar spring
  • Suspension control ECU
  • Wire harness

Fail-safe function:

If a trouble occurs, the height control is prohibited after adjusting the vehicle to the standard height in case that the height is higher than the standard or to the lowest wheel of the 4 wheels in case that the height is lower than the standard.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK FLUID LEVEL OF THE RESERVOIR TANK

(a) Refer to "Check Fluid Level of the Reservoir Tank" procedure 2006 MY LX470 [05/2005 -        ]; SUSPENSION: SUSPENSION FLUID: BLEEDING .

NG

FILL THE RESERVOIR TANK WITH SUSPENSION FLUID AHC

OK

2.

CHECK FLUID LEAKAGE

(a) Refer to procedure 2006 MY LX470 [05/2005 -        ]; SUSPENSION CONTROL: ACTIVE HEIGHT CONTROL SUSPENSION: ON-VEHICLE INSPECTION+ .

NG

REPAIR OR REPLACE THE PART WITH FLUID LEAKAGE

OK

3.

CHECK HEIGHT CONTROL SENSOR LINK

(a) Refer to "Adjust Height Control Sensor Link" procedure 2006 MY LX470 [05/2005 -        ]; SUSPENSION CONTROL: HEIGHT CONTROL SENSOR: ADJUSTMENT .

NG

REPAIR OR REPLACE HEIGHT CONTROL SENSOR LINK

OK

4.

CHECK FLUID DELIVERY PRESSURE OF THE AHC PUMP AND MOTOR

(a) Check that the fluid pressure raises by raising the vehicle height with the height select switch with the same procedure as the torsion bar spring adjustment 2006 MY LX470 [05/2005 -        ]; SUSPENSION CONTROL: HEIGHT CONTROL SENSOR: ADJUSTMENT .

NG

REPLACE AHC PUMP AND MOTOR

OK

5.

INSPECT AHC MOTOR RELAY (Marking: AHC)

(a) Remove the AHC motor relay from the engine room junction block.

(b) Measure the resistance between each pair of terminal of the motor relay.

Standard resistance:

Tester Connection

Specified Condition

3 - 4

Reference value 62 Ω

1 - 2

10 kΩ or higher

(c) Apply battery positive voltage between terminals 3 and 4.

(d) Measure the resistance between terminals 1 and 2.

Standard resistance:

Tester Connection

Specified Condition

1 - 2

Below 1 Ω
NG

REPLACE AHC MOTOR RELAY

OK

6.

CHECK WIRE HARNESS (AHC PUMP AND MOTOR AND SUSPENSION CONTROL ECU - AHC MOTOR RELAY AND BATTERY)
NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE SUSPENSION CONTROL ECU