I would agree with swoop223, especially if this truck was a newer truck, however being as this is not a fortis but a d187v (XM) series serial number, there may not be as much information on the dash, and 'old school' troubleshooting may be every bit as valid a way to go. please tell us about the power going to the LPG lock-off, and if it stays powered up as the unit shuts down.