Three lines, a handful of words, and almost everything is left for the reader to feel. The poem sets up a comparison: ice sitting on ice, then "my heart" and "my car." The structure suggests the heart and the car are the two layers, one frozen thing resting on another. Or perhaps both are simply examples of the same coldness.
The title, "Pimp," changes how we read it. It points toward a hard, flashy image: a polished car, a show of status, a person who guards feelings behind a slick surface. Ice also suggests jewelry and shine, so the cold here is both glittering and lifeless. The speaker seems to equate their heart with their car: impressive from outside, chilly and unyielding within.
The mood is detached and a little bleak. There's no explanation and no complaint, just a flat statement. That calm tone makes the emptiness feel more convincing, as if the speaker has gotten used to it.