- With the height control valve inactivated, an open signal of the height control valve is detected for 1 second or more.
- With the height control valve activated, a short signal of the valve is detected 8 times successively.
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Suspension | Section: Suspension Control System | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000001N9D003X |
| Title: SUSPENSION CONTROL: AIR SUSPENSION SYSTEM (w/o AVS): DESCRIPTION (2008 Sequoia) | ||
|
DTC |
C1747 |
Leveling Solenoid Valve Circuit Malfunction |
DESCRIPTION
The suspension control ECU opens the leveling solenoid valve (No. 2 height control valve) to lead the compressed air to the height control cylinder (pneumatic cylinder) and to raise the vehicle height.
The No. 2 height control valve consists of a leveling solenoid valve and a gate solenoid valve.
The leveling solenoid valve opens and closes the passage between the compressor and the height control cylinder (pneumatic cylinder).
|
DTC Code |
Detection Condition |
Trouble Area |
|---|---|---|
|
C1747 |
When either of the following is detected: |
|
HINT:
- Once the ECU stores DTC C1747 in the memory, the vehicle height control is suspended until a normal signal is input to the ECU from the height control solenoid valves. However, control is resumed if the ignition switch is turned off, then to ON again.
-
Malfunction in the leveling solenoid valve:
The height control operation is suspended, and the height control indicator light does not change by operating the height control switch.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
-
If DTC C1781 (ECU malfunction) and/or C1782 (power source circuit) is displayed, perform the inspection necessary for DTC C1781
and/or C1782
first.
- If DTC C1781 and the C1782 are output at the same time, perform the inspection necessary for DTC C1782 first.
PROCEDURE
|
1. |
PERFORM ACTIVE TEST USING TECHSTREAM (REAR LEVELING 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 |
|---|---|---|---|
|
Rear Leveling Solenoid |
Leveling 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 |
|
|
2. |
INSPECT NO. 2 HEIGHT CONTROL VALVE SUB-ASSEMBLY (LEVELING SOLENOID VALVE) |
(a) Turn the ignition switch off.
|
(b) Disconnect Q4 solenoid valve connector. |
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
2 (E) - 3 (RH+) |
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
|
|
3. |
CHECK HARNESS AND CONNECTOR (LEVELING SOLENOID VALVE - ECU AND BODY GROUND) |
|
(a) Disconnect the O19 ECU connector. |
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
Q4-3 (RH+) - O19-3 (SLRR) |
Always |
Below 1 Ω |
|
Q4-3 (RH+) or O19-3 (SLRR) - Body ground |
Always |
10 kΩ or higher |
|
Q4-2 (E) - Body ground |
Always |
Below 1 Ω |
|
|
|