KTM 990 SUPERMOTO T EU Owner's Manual page 189

22 ENGINE CONTROL BLINK CODE
Blink code of FI warning
lamp (MIL)
Error level condition
Blink code of FI warning
lamp (MIL)
Error level condition
81 FI warning lamp (MIL) flashes 8x long, 1x short
Immobilizer control unit - circuit fault
91 FI warning lamp (MIL) flashes 9x long, 1x short
CAN bus communication error
187