Being an extension of the primary Transformer wouldn't make them at all sentient/sapient -- at best they'd be artificially intelligent. These components are like an extension of that Transformer's body or mind - kinda like the avatars from James Cameron's Avatar film. Pretenders can feel pain if their Shell is damaged (if anything the pain is amplified); a weakness exploited by Thunderwing when he blasted Bumblebee's shell, knocking 'Bee unconscious without even having to touch him. Likewise Carnivac was rendered temporarily unconscious due to the overwhelming pain he felt when he sacrificed his Pretender shell; and the fact that Carnivac was willing to endanger his shell like that indicates that there's no moral issues arising from the shell possessing any level of sentience (after all, not even Decepticon Target/Head/Powermasters will wantonly sacrifice their sapient Nebulan partners).
Roller and Combat Deck are essentially 'drones' for Optimus Prime, with Optimus Prime himself being the primary Transformer possessing sapience/sentience. Evidence that might suggest a lack of sentience in Optimus Prime's secondary components include:
+ The original tech specs describes the cab/robot as the "brain centre," suggesting that he is the sentient/sapient module.
+ Optimus Prime's G1 TFU profile states that "the Optimus module is by far the most important component of the trio. Although he could survive without the other two, they could not survive without him."
+ In "More Than Meets The Eye Part 3," Megatron destroys Combat Deck's artillery robot with a blast from his fusion cannon. Optimus Prime just shrugs it off and keeps fighting. He doesn't show any emotional reaction to it at all, either at the time or later on. Optimus Prime didn't even flinch when it happened! Either the pain feedback must've been reduced (so like the reverse of what happens with Pretenders), or he's just incredibly good at shrugging off paint ("'Tis but a flesh wound!")
+ In the IDWverse, Optimus Prime was able to transfer his consciousness into Combat Deck temporarily, and then transferred it back into the cab/robot component again.
+ eHobby retconned Roller as having originally been a non-sentient industrial droid known as Barrelroller which Orion Pax used as an electromagnetic lifter. Ditto in the Wings universe.
+ Nobody ever cares where Combat Deck and Roller bugger off to when Optimus Prime is in robot mode! They could back roll into a ditch and noone would check.
So yeah, if Action Master Partners are going to be autonomous components like Combat Deck and Roller, then I'd say that they'd be artificially intelligent but non-sentient/sapient modules. It'd suck if an Action Master felt pain from damage dealt to their partner... (e.g. if Attack Copter or Gatoraider were damaged, would Over-Run and Krok feel their pain?).
Having said that, there's at least one arguably 2 pieces of canonical evidence I can think of that might suggest the contrary about Optimus Prime:
1) In "Attack of the Autobots," the Autobots had to attach attitude exchangers to all of Optimus Prime's components, not just the Prime module. Does this mean that Prime's consciousness is spread among his three components? If so that would contradict the events of MTMTE#3 (of course, the G1 cartoon is chock full of continuity contradictions![]()
)... otherwise we could theorise that while it's only Optimus who's sentient/sapient, the other components themselves were still fueled with "evil energy" and needed the attitude exchanger to convert their fuel to "good."
Or this: http://www.scaryforkids.com/pics/kru...e-clown-14.jpg
2) In the IDWverse, Orion Pax knew another Autobot called Roller. But whether that Autobot became Optimus Prime's Roller or if he was just an Autobot who coincidentally has the same name as Optimus Prime's scout component (or maybe Prime named his scout car after him as a tribute?) is unknown. There's nothing to say that an Action Master partner can't be fully sapient... but there just doesn't seem to be sufficient evidence to state that they are.