DTC C1791-91: Adaptive Variable Suspension (AVS) Switch Circuit (Test Mode DTC) [08/2015 - 08/2019]: Procedure

1. Turn the engine switch off.
2. Connect the Techstream to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the Techstream on.
5. Enter the following menus: Chassis / Air suspension / Data List.
   AIR SUSPENSION
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Damping Control Switch	Absorber control switch / NORMAL, COMFORT or SPORT	Indicates current absorber control switch position	-

6. Check that the value displayed on the Techstream changes by operating the absorber control switch between COMF, NORMAL and SPORT.

   OK

   Absorber control switch value changes.

Result: 

OK 

USE SIMULATION METHOD TO CHECK 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2019] )

Result: 

NG 

See step  2

1. Turn the engine switch off.
2. Remove the combination switch (Refer to REMOVAL [08/2015 - 08/2021] ).
3. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   9 (E) - 11 (ECU2)	COMF position	Below 1 Ω
   	Normal position	10 kΩ or higher
   9 (E) - 1 (ECU1)	SPORT position	Below 1 Ω
   	Normal position	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Absorber Control Switch [Combination Switch])

Result: 

NG 

REPLACE COMBINATION SWITCH ASSEMBLY 

(Refer to REMOVAL [08/2015 - 08/2021] )

Result: 

OK 

See step  3

1. Disconnect the i5 combination switch connector.
2. Disconnect the A40 suspension control ECU connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   i5-1 (ECU1) - A40-23 (TSW1)	Always	Below 1 Ω
   i5-11 (ECU2) - A40-22 (TSW2)	Always	Below 1 Ω
   i5-9 (E) - Body ground	Always	Below 1 Ω
   i5-1 (ECU1) - Body ground	Always	10 kΩ or higher
   i5-11 (ECU2) - Body ground	Always	10 kΩ or higher

Result: 

OK 

REPLACE SUSPENSION CONTROL ECU 

(Refer to REMOVAL [08/2015 - ] )

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR