DTC C1741: Front Height Control Solenoid Valve RH Circuit Malfunction; DTC C1742: Front Height Control Solenoid Valve LH Circuit Malfunction (TO 08/2009): Procedure

1. Disconnect the height control valve No. 1 connector.
   Fig 1: Inspecting Height Control Valve No. 1

   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
   3 (RH+) - 2 (E)	at 15 to 25°C (59 to 77°F)	10 to 14 Ω

   C1742:
   
   

   Tester Connection	Condition	Specified Condition
   1 (LH+) - 2 (E)	at 15 to 25°C (59 to 77°F)	10 to 14 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Height Control Valve No. 1)

3. Check the front RH valve (C1741).
   1. Connect a positive (+) lead from the battery to terminal 3 (RH+) and a negative (-) lead to terminal 2 (E).
   2. Check the operating sound of the height control valve No. 1.

      OK

      It makes an operating sound (click).

4. Check the front LH valve (C1742).
   1. Connect a positive (+) lead from the battery to terminal 1 (LH+) and a negative (-) lead to terminal 2 (E).
   2. Check the operating sound of the height control valve No. 1.

      OK

      It makes an operating sound (click).

NG → See step   4 

OK: Go to next step 

1. Disconnect the A54 ECU connector.
2. Disconnect the A10 height control valve No. 1 connector.
3. Measure the resistance according to the values in the table below.
   Fig 2: Identifying A54 ECU And A10 Height Control Valve No. 1 Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance

   C1741:
   
   

   Tester Connection	Condition	Specified Condition
   A54-12 (SLFR) - A10-3 (RH+)	Always	Below 1 Ω
   A54-12 (SLFR) - Body ground	Always	10 kΩ or higher
   A10-2 (E) - Body ground	Always	Below 1 Ω

   C1742:
   
   

   Tester Connection	Condition	Specified Condition
   A54-11 (SLFL) - A10-1 (LH+)	Always	Below 1 Ω
   A54-11 (SLFL) - Body ground	Always	10 kΩ or higher
   A10-2 (E) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Height Control Valve No. 1)
   *2	Rear view of wire harness connector (to Suspension Control ECU)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   3