I don't think you need a scan tool...i am not at work right now ,where i could ask one of the techs.i'am pretty sure that u turn key on to access. press on gas pedal 3 times the turn key off...hope this helps...Alan

-1967 Plymouth Satellite #3555
446 cid on E-85
best 1/4 et 10.577 @ 127.58
best 1/8 et 6.722 @ 100.68
best 60ft. 1.419