Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM000001CU6004X
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: SUSPENSION CONTROL: ACTIVE HEIGHT CONTROL SUSPENSION: C1721/21,C1723/23; Front Damping Force Control Actuator Circuit Malfunction; 2007 MY LX470 [08/2006 -        ]

DTC

C1721/21

Front Damping Force Control Actuator Circuit Malfunction

DTC

C1723/23

Rear Damping Force Control Actuator Circuit Malfunction

DESCRIPTION

The ECU sends a signal to the damping force control actuator to drive the rotary valve of the shock absorber changing the shock absorber damping force.

The actuator is driven electromagnetically by step motor so that it can accurately follow the driving conditions that change frequently.

DTC No.

DTC Detection Condition

Trouble Area

C1721/21

When detecting the over current detection condition (When the condition that the current between the actuator drive terminal of ECU and GND is 3.5 to 6.0 A or more continued for 1 +- 0.5 msec.) 10 times continuously.
  • Front damping force control actuator
  • Suspension control ECU
  • Wire harness

C1723/23

When detecting the over current detection condition (When the condition that the current between the actuator drive terminal of ECU and GND is 3.5 to 6.0 A or more continued for 1 +- 0.5 msec.) 10 times continuously.
  • Rear damping force control actuator
  • Suspension control ECU
  • Wire harness

HINT:

  • DTC C1721/21 corresponds to the front damping force control actuator circuit.
  • DTC C1723/23 corresponds to the rear damping force control actuator circuit.

Fail-safe function:

If a trouble occurs in the front or rear wheel damping force control actuator circuit, the ECU prohibits the damping force control after the ECU has returned the damping force of the other side wheel to the normal condition.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (SHOCK ABSORBER)

(a) Using the same method as used for the DAMPING FORCE CONTROLLING CHECK 2007 MY LX470 [08/2006 -        ]; SUSPENSION CONTROL: ACTIVE HEIGHT CONTROL SUSPENSION: TEST MODE PROCEDURE , bounce the vehicle and check that the shock absorber becoming harder.

OK

REPLACE SUSPENSION CONTROL ECU

NG

2.

CHECK WIRE HARNESS (DAMPING FORCE CONTROL ACTUATOR (FRONT AND REAR) - SUSPENSION CONTROL ECU)
NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

3.

INSPECT DAMPING FORCE CONTROL ACTUATOR (FRONT AND REAR)

(a) Disconnect the damping force control actuator connector.

(b) Measure the resistance between each terminal of the damping force control actuator.

Standard resistance:

Tester Connection

Specified Condition

1 - 2

12.0 to 13.6 Ω

2 - 3

12.0 to 13.6 Ω

2 - 4

12.0 to 13.6 Ω

2 - 5

12.0 to 13.6 Ω
NG

REPLACE DAMPING FORCE CONTROL ACTUATOR (FRONT OR REAR)

OK

REPLACE SUSPENSION CONTROL ECU