DTC C1786/86: Height Control Switch Circuit: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to the ON position, and push the Techstream main switch on,
3. Select the item below in the DATA LIST, and read its value displayed on the Techstream.

   Air suspension

   Item	Normal Condition
   Height Control SW (Down)	ON: Height control switch while pressing "DOWN" button OFF: Neutral position
   Height Control SW (Up)	ON: Height control switch while pressing "UP" button OFF: Neutral position

4. Check that the value displayed on the Techstream changes by pressing the height control switch "UP" or "DOWN".

   OK

   Height control switch value changes.

NG → Go to next step 

OK → REPLACE SUSPENSION CONTROL ECU 

1. Disconnect the height control switch connector.
   Fig 1: Identifying Height Control Switch & Connector Terminals

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

   Standard resistance

   Switch Condition	Tester Connection	Specified Condition
   "Down" button	1 (IGH) - 3 (LSW)	Below 1 Ω
   OFF	1 (IGH) - 3 (LSW) 1 (IGH) - 6 (HSW)	10 kΩ or higher
   "UP" button	1 (IGH) - 6 (HSW)	Below 1 Ω

NG → REPLACE HEIGHT CONTROL SWITCH 

OK: Go to next step 

1. Disconnect the suspension control ECU S15 connector.
   Fig 2: Identifying Suspension Control ECU S15 Connector Terminals

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

   Standard resistance

   Tester Connection	Specified Condition
   S15-15 (DNSW) - H22-3 (LSW)	Below 1 Ω
   S15-16 (UPSW) - H22-6 (HSW)	Below 1 Ω
   S15-15 (DNSW) - Body ground	10 kΩ or higher
   S15-16 (UPSW) - Body ground	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Measure the resistance according to the values in the table below.
   Fig 3: Identifying Height Control Switch Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance

   Tester Connection	Specified Condition
   H22-1 (IGH) - Body ground	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE SUSPENSION CONTROL ECU