DTC C1741: Front Height Control Solenoid Valve RH Circuit Malfunction; DTC C1742: Front Height Control Solenoid Valve LH Circuit Malfunction: Procedure

1. Clear the DTC. Refer to DTC CHECK / CLEAR .

NEXT: Go to next step 

1. Turn the engine switch off.
2. Connect the Techstream to the DLC3.
3. Turn the engine switch on (IG) and the Techstream on.
4. Enter the following menus: Chassis / Air suspension / Active Test.
5. According to the display on the Techstream, perform the "Active Test"
6. Check the operation sound of the height control solenoid valve when the solenoid is turned on through the Active Test.
   AIR SUSPENSION
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Front Right Solenoid	Turn OFF front solenoid valve RH 1 second after turning it ON	-	Operation of solenoid (clicking sound) can be heard
   Front Left Solenoid	Turn OFF front solenoid valve LH 1 second after turning it ON	-	Operation of solenoid (clicking sound) can be heard

   OK

   An operation sound is heard 1 second after the height control solenoid valve is turned on.

NG → See step   4 

OK: Go to next step 

1. Perform a road test.
2. Check for DTC. Refer to DTC CHECK / CLEAR .

   Result

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

B → See step   8 

A: Go to next step 

1. Remove the front height control valve. Refer to REMOVAL .
   Fig 1: Identifying Front Height Control Valve Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the values in the table below.

   Standard resistance

   C1741:
   
   

   Tester Connection	Condition	Specified Condition
   1 (RH+) - 2 (E)	at 20 °C (68°F)	10 to 14 Ω

   C1742:
   
   

   Tester Connection	Condition	Specified Condition
   3 (LH+) - 2 (E)	at 20 °C (68°F)	10 to 14 Ω

NG → See step   6 

OK: Go to next step 

1. Disconnect the L88 ECU connector.
2. Disconnect the A59 height control valve connector.
3. Measure the resistance according to the values in the table below.

   Standard resistance

   C1741:
   
   

   Tester Connection	Condition	Specified Condition
   L88-16 (SLFR) - A59-1 (RH+)	Always	Below 1 Ω
   L88-16 (SLFR) or A59-1 (RH+) - Body ground	Always	10 kΩ or higher
   A59-2 (E) - Body ground	Always	Below 1 Ω

   C1742:
   
   

   Tester Connection	Condition	Specified Condition
   L88-17 (SLFL) - A59-3 (LH+)	Always	Below 1 Ω
   L88-17 (SLFL) or A59-3 (LH+) - Body ground	Always	10 kΩ or higher
   A59-2 (E) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   7