Next time it does not start, tap the OVP relay...VERY COMMON fault ....

Also, next time it doesn't start, cycle the key a few times before attempting to crank it over....if it then starts OVP is suspect.
On that chassis , nothing works with a bad OVP, except starter.
Security is only starter LOCK OUT ..nothing to do with fuel or spark.
If it cranks , forget about the Security System [ ATA]

The OVP is behind the plastic panel , behind the battery. Fuse on top.

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A Dalton