Hello Popough!
The O/D light's flashing means a kind of transmission trouble.
You can find some useful PDFs in
carsoft.co.il/my/SUZUKI/SUZUKI%20VITARA.zipOne of them is a complete auto trans diagnosis guide which contains the trouble codes too.
The codes are:
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Trouble Code (1) Probable Cause
12 ............................... System Operation Normal
21 ..................... No. 1 Shift Solenoid Open Circuit
22 .................... No. 1 Shift Solenoid Short Circuit
23 ..................... No. 2 Shift Solenoid Open Circuit
24 .................... No. 2 Shift Solenoid Short Circuit
25 ............................. TCC Solenoid Open Circuit
26 ............................ TCC Solenoid Short Circuit
31 ............ Vehicle Speed Sensor Open Or Short Circuit
32 ................ Throttle Position Sensor Short Circuit
33 ................. Throttle Position Sensor Open Circuit
34 ................ Defective Park/Neutral Position Switch
36 .............. (2) No Signal-Both Vehicle Speed Sensors
(1) - Check listed component for probable cause. Also check wiring and connections of specified component.
(2) - No signal from both transmission and speedometer mounted vehicle speed sensors.
If a trouble code is present, OD OFF light will flash a
trouble code. The number of flashes will equal first digit of trouble code. After a one second pause, second digit will be displayed.
If more than one trouble code is present, next trouble
code will be displayed after a 3 second pause. Smallest number trouble code will be displayed first. Trouble codes will be repeated.
Good luck and have soon a running car!