DTC (detected trouble code) C40 indicates an issue with the ISC Valve (idle speed control valve).
Would help to have the P code....you would need S.D.S suzuki diagnostic system interface, the software and a laptop to access this and most likely to clear the diagnostic trouble code once repaired. Not the end of the world but you may be paying a visit to a dealer to have it sorted out. See below.
Could be one of the following.
1-If the ECM coupler is disconnected within 5 seconds after ignition switch is turned to OFF, there is a possibility of an unusual value being written in the ECM and causing an error of ISC valve operation.
2-ISC valve circuit open or shorted to ground.
3-Idle speed is lower than the desired idle
speed.
4-Air passage clogged.
5-ISC valve is fixed.
6-ISC valve preset position is incorrect.
7-Idle speed is higher than the desired idle
speed.