DTC C1748: Low Pressure Tank Valve (TO 08/2009): Procedure

1. Turn the engine switch off.
2. Disconnect the low pressure tank valve connector.
   Fig 1: Inspecting Pneumatic W/Tube Tank Assembly (Low Pressure Tank Valve)

   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
   2 (B) - 1 (L)	15 to 25°C (59 to 77°F)	10 to 14 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Low Pressure Tank Valve)

4. Inspect if the low pressure tank valve is stuck :
   1. Connect a positive (+) lead from the battery to terminal 2 (B) and a negative (-) lead to terminal 1 (L).
   2. Check the operating sound of the low pressure tank valve.

      OK

      It makes an operating sound (click).

NG → See step   4 

OK: Go to next step 

1. Turn the engine switch off.
2. Disconnect the A54 ECU connector.
3. Disconnect the O11 low pressure tank valve connector.
4. Measure the resistance according to the value(s) in the table below.
   Fig 2: Identifying A54 ECU Connector And O11 Low Pressure Tank Valve Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance

   Tester Connection	Condition	Specified Condition
   O11-2 (B) - A54-20 (SLLO)	Always	Below 1 Ω
   A54-20 (SLLO) - Body ground	Always	10 kΩ or higher
   O11-1 (L) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Low Pressure Tank Valve)
   *2	Rear view of wire harness connector (to Suspension Control ECU)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   3