Last Modified: 11-29-2007 1.6 C
Service Category: Suspension Section: Suspension Control System
Model Year: 2008 Model: Sequoia Doc ID: RM000001N95004X
Title: SUSPENSION CONTROL: AIR SUSPENSION SYSTEM (w/ AVS): DESCRIPTION (2008 Sequoia)

DTC

C1745

Exhaust Solenoid Valve Circuit Malfunction

DESCRIPTION

The suspension control ECU operates the exhaust solenoid valve (height control compressor), releases the air from the height control cylinder assembly (pneumatic cylinder), and lowers vehicle height.

When the vehicle height is lowered, the suspension control ECU opens the height control valve and then operates the exhaust solenoid valve to release the compressed air to the outside.

The exhaust solenoid valve is on the compressor unit and has only one valve.

DTC Code

Detection Condition

Trouble Area

C1745

When either of the following is detected:

  • With the exhaust valve not activated, an open signal of the exhaust valve is detected for 1 second or more.
  • With the exhaust valve activated, a short signal of the exhaust valve is detected 8 times successively.
  • Wire harness or connector
  • Exhaust solenoid valve (Height control compressor)
  • Suspension control ECU

HINT:

  • Once the ECU stores DTC C1745 in the memory, the vehicle height control is suspended until a normal signal is input to the ECU from the exhaust solenoid valve. However, control is resumed if the ignition switch is turned off, then to ON again.
  • Malfunction in the exhaust solenoid valve:

    The height control indicator light "N" comes on or blinks, and "HI" and "LO" do not come on by operating the height control switch "UP" or "DOWN".

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM (EXHAUST SOLENOID)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON, and turn the Techstream main switch on.

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

Air Suspension

Tester Display

Test Part

Control Range

Diagnostic Note

Exhaust Solenoid

Exhaust solenoid valve

ON or OFF

Operation sound of solenoid (clicking sound) can be heard

OK:

Operation of solenoid (clicking sound) can be heard

Result

Result

Proceed to

NG

A

OK (When troubleshooting according to the Problem Symptoms Table)

B

OK (When troubleshooting according to the DTC Chart)

C
A

2.

INSPECT NO. 1 HEIGHT CONTROL COMPRESSOR (EXHAUST SOLENOID VALVE)

(a) Turn the ignition switch off.

(b) Disconnect Q3 solenoid valve connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1(B) - 2 (L)

20°C (68°F)

10 to 14 Ω

(d) Connect the battery positive (+) lead to terminal 1 and the negative (-) lead to terminal 2 of the solenoid valve connector. Then check that the valve makes an operating sound.

OK:

Operation of solenoid (clicking sound) can be heard

OK

3.

CHECK HARNESS AND CONNECTOR (EXHAUST SOLENOID VALVE - ECU AND BODY GROUND)

(a) Disconnect the O16 ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Q3-1 (B) - O16-8 (SLEX)

Always

Below 1 Ω

Q3-1 (B) or O16-8 (SLEX) - Body ground

Always

10 kΩ or higher

Q3-2 (L) - Body ground

Always

Below 1 Ω
OK