My 1998 Jaguar reads Fail Safe Mode and if I restart it why will it go off?

The "Fail Safe Mode" in your 1998 Jaguar indicates that the vehicle's onboard computer has detected a fault in the engine management system, prompting it to limit performance to protect the engine. Restarting the car may temporarily clear the error and allow normal operation, but if the underlying issue isn't resolved, the warning may reappear. It's advisable to have the vehicle diagnosed with a professional scanner to identify and fix the root cause of the problem. Ignoring it could lead to more serious damage or performance issues.