DTC C1746: Gate Solenoid Valve Circuit Malfunction [08/2015 - 08/2019]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON, and turn the Techstream main switch on.
3. Enter the following menus: Chassis / Air suspension / Active Test.
   AIR SUSPENSION
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Rear Gate Solenoid	Gate 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

Result: 

B 

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [08/2015 - ] )

Result: 

C 

USE SIMULATION METHOD TO CHECK 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2017] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2017 - 08/2018] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2018 - 08/2019] )

Result: 

A 

See step  2

1. Turn the ignition switch off.
2. Disconnect Q4 solenoid valve connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1 (LH+) - 2 (E)	20°C (68°F)	17.5 to 21.5 Ω

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

   OK

   Operation of solenoid (clicking sound) can be heard

Result: 

NG 

REPLACE NO. 2 HEIGHT CONTROL VALVE SUB-ASSEMBLY 

(Refer to REMOVAL [08/2015 - ] )

Result: 

OK 

See step  3

1. Disconnect the O17 ECU connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Q4-1 (LH+) - O17-15 (SLRL)	Always	Below 1 Ω
   Q4-1 (LH+) or O17-15 (SLRL) - Body ground	Always	10 kΩ or higher
   Q4-2 (E) - Body ground	Always	Below 1 Ω

Result: 

OK 

REPLACE SUSPENSION CONTROL ECU 

(Refer to REMOVAL [08/2015 - ] )

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR