SUSPENSION CONTROL: ACTIVE HEIGHT CONTROL SUSPENSION: DESCRIPTION (2008 LX570)

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Last Modified: 11-27-2007		1.6 C
Service Category: Suspension	Section: Suspension Control System
Model Year: 2008	Model: LX570	Doc ID: RM000001CU7006X
Title: SUSPENSION CONTROL: ACTIVE HEIGHT CONTROL SUSPENSION: DESCRIPTION (2008 LX570)

DTC

C1741

Front Height Control Solenoid Valve RH Circuit Malfunction

DTC

C1742

Front Height Control Solenoid Valve LH Circuit Malfunction

DTC

C1743

Rear Height Control Solenoid Valve RH Circuit Malfunction

DTC

C1744

Rear Height Control Solenoid Valve LH Circuit Malfunction

DTC

C1753

Accumulator Solenoid Valve Malfunction

DTC

C1754

Front Gate Solenoid Valve Malfunction

DTC

C1755

Rear Gate Solenoid Valve Malfunction

DESCRIPTION

The control valve solenoid assembly consists of each front and rear leveling valve, gate valve and accumulator valve. It performs the height control and connects and disconnects the fluid line of the right and left shock absorber by operating the solenoid valve with the control signal from the ECU.

DTC Code	Detection Condition	Trouble Area
C1741	When either of the following is detected: With the front leveling valve RH not activated, an open signal of the front leveling valve RH is detected for 1 second or more. With the front leveling valve RH activated, a short signal of the front leveling valve RH is detected 8 times successively.	Harness or connector No. 1 height control valve Suspension control ECU Each front suspension control valve (Each front spring rate switching valve)
C1742	When either of the following is detected: With the front leveling valve LH not activated, an open signal of the front leveling valve LH is detected for 1 second or more. With the front leveling valve LH activated, a short signal of the front leveling valve LH is detected 8 times successively.	Harness or connector No. 1 height control valve Suspension control ECU Each front suspension control valve (Each front spring rate switching valve)
C1743	When either of the following is detected: With the rear leveling valve RH not activated, an open signal of the rear leveling valve RH is detected for 1 second or more. With the rear leveling valve RH activated, a short signal of the rear leveling valve RH is detected 8 times successively.	Harness or connector No. 1 height control valve Suspension control ECU Each front suspension control valve (Each front spring rate switching valve)
C1744	When either of the following is detected: With the rear leveling valve LH not activated, an open signal of the rear leveling valve LH is detected for 1 second or more. With the rear leveling valve LH activated, a short signal of the rear leveling valve LH is detected 8 times successively.	Harness or connector No. 1 height control valve Suspension control ECU Each front suspension control valve (Each front spring rate switching valve)
C1753	When either of the following is detected: With the accumulator valve not activated, an open signal of the accumulator valve is detected for 1 second or more. With the accumulator valve activated, a short signal of the accumulator valve is detected 8 times successively.	Harness or connector No. 1 height control valve Suspension control ECU Each front suspension control valve (Each front spring rate switching valve)
C1754	When either of the following is detected: With the front gate valve not activated, an open signal of the front gate valve is detected for 1 second or more. With the front gate valve activated, a short signal of the front gate valve is detected 8 times successively.	Harness or connector No. 1 height control valve Suspension control ECU Each front suspension control valve (Each front spring rate switching valve)
C1755	When either of the following is detected: With the rear gate valve not activated, an open signal of the rear gate valve is detected for 1 second or more. With the rear gate valve activated, a short signal of the rear gate valve is detected 8 times successively.	Harness or connector No. 1 height control valve Suspension control ECU Each front suspension control valve (Each front spring rate switching valve)

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

Before performing troubleshooting, inspect the connectors of related circuits.

If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed .

HINT:

Power is supplied to the No. 1 height control valve and front suspension control valve from the suspension control ECU. If a short occurs in the power supply circuit in the front suspension control valve, DTC C1741, C1742, C1743, C1744, C1753, C1754 and/or C1755 will be stored. In this case, DTC C1736 and/or C1737 will also be stored.

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM (NO. 1 HEIGHT CONTROL VALVE)

(a) Turn the engine switch off.

(b) Connect the Techstream to the DLC3.

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

(e) Check the operation of the leveling valve solenoid, accumulator valve solenoid and gate valve solenoid when operating the solenoid with the Techstream.

AHC

Tester Display	Test Part	Control Range	Diagnostic Note
Front Right Height Solenoid	Front height control solenoid valve RH	ON or OFF	Operation of the solenoid can be heard.
Front Left Height Solenoid	Front height control solenoid valve LH	ON or OFF	Operation of the solenoid can be heard.
Rear Right Height Solenoid	Rear height control solenoid valve RH	ON or OFF	Operation of the solenoid can be heard.
Rear Left Height Solenoid	Rear height control solenoid valve LH	ON or OFF	Operation of the solenoid can be heard.
Accumulator Valve	Accumulator solenoid valve	ON or OFF	Operation of the 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 solenoid and/or gate valve solenoid operates.

2.	RECONFIRM DTC OUTPUT

(a) Clear the DTCs .

(b) Perform a road test.

Result

Result	Proceed to
DTC is output	A
DTC is not output	B

3.	CHECK HARNESS AND CONNECTOR (NO. 1 HEIGHT CONTROL VALVE - SUSPENSION CONTROL ECU)

(a) Disconnect the N3 No. 1 height control valve connector.

(b) Disconnect the K32 ECU connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
K32-1 (SLB) - N3-6 (SLB)	Always	Below 1 Ω
K32-7 (SLFR) - N3-4 (SLFR)	Always	Below 1 Ω
K32-7 (SLFR) - Body ground	Always	10 kΩ or higher
K32-8 (SLFL) - N3-3 (SLFL)	Always	Below 1 Ω
K32-8 (SLFL) - Body ground	Always	10 kΩ or higher
K32-9 (SLRR) - N3-1 (SLRR)	Always	Below 1 Ω
K32-9 (SLRR) - Body ground	Always	10 kΩ or higher
K32-10 (SLAC) - N3-7 (AHC-)	Always	Below 1 Ω
K32-10 (SLAC) - Body ground	Always	10 kΩ or higher
K32-22 (SLRL) - N3-2 (SLRL)	Always	Below 1 Ω
K32-22 (SLRL) - Body ground	Always	10 kΩ or higher
K32-29 (SLRG) - N3-5 (SLRG)	Always	Below 1 Ω
K32-29 (SLRG) - Body ground	Always	10 kΩ or higher
K32-30 (SLFG) - N3-8 (SLFG)	Always	Below 1 Ω
K32-30 (SLFG) - Body ground	Always	10 kΩ or higher

4.	CHECK HARNESS AND CONNECTOR (BODY GROUND BETWEEN ECU - NO. 1 HEIGHT CONTROL VALVE)

(a) Disconnect the N3 No. 1 height control valve connector.

(b) Disconnect the K32 ECU connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
K32-1 (SLB) - Body ground	Always	10 kΩ or higher

5.	INSPECT NO. 1 HEIGHT CONTROL VALVE

(a) Connect the N3 No. 1 height control valve connector.

(b) Disconnect the K32 ECU connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
K32-7 (SLFR) - K32-1 (SLB)	Always	3.0 to 3.8 Ω
K32-7 (SLFR) - Body ground	Always	10 kΩ or higher
K32-8 (SLFL) - K32-1 (SLB)	Always	3.0 to 3.8 Ω
K32-8 (SLFL) - Body ground	Always	10 kΩ or higher
K32-9 (SLRR) - K32-1 (SLB)	Always	3.0 to 3.8 Ω
K32-9 (SLRR) - Body ground	Always	10 kΩ or higher
K32-10 (SLAC) - K32-1 (SLB)	Always	3.0 to 3.8 Ω
K32-10 (SLAC) - Body ground	Always	10 kΩ or higher
K32-22 (SLRL) - K32-1 (SLB)	Always	3.0 to 3.8 Ω
K32-22 (SLRL) - Body ground	Always	10 kΩ or higher
K32-29 (SLRG) - K32-1 (SLB)	Always	3.0 to 3.8 Ω
K32-29 (SLRG) - Body ground	Always	10 kΩ or higher
K32-30 (SLFG) - K32-1 (SLB)	Always	3.0 to 3.8 Ω
K32-30 (SLFG) - Body ground	Always	10 kΩ or higher
K32-1 (SLB) - Body ground	Always	10 kΩ or higher

6.	CHECK HARNESS AND CONNECTOR (BODY GROUND BETWEEN ECU - FRONT SUSPENSION CONTROL VALVE)

(a) Disconnect the N9 and N11 front suspension control valve connectors.

(b) Disconnect the N3 No. 1 height control valve connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
K32-1 (SLB) - Body ground	Always	10 kΩ or higher

7.	CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - FRONT SUSPENSION CONTROL VALVE)