  We associate two modules, the $G$-parking critical module and the toppling
critical module, to an undirected connected graph $G$. The $G$-parking critical
module and the toppling critical module are canonical modules (with suitable
twists) of quotient rings of the well-studied $G$-parking function ideal and
the toppling ideal, respectively. For each critical module, we establish a
Tutte-like short exact sequence relating the modules associated to $G$, an edge
contraction $G/e$ and an edge deletion $G \setminus e$ ($e$ is a non-bridge).
We obtain purely combinatorial consequences of Tutte short exact sequences. For
instance, we reprove a theorem of Merino that the critical polynomial of a
graph is an evaluation of its Tutte polynomial, and relate the vanishing of
certain combinatorial invariants (the number of acyclic orientations on
connected partition graphs satisfying a unique sink property) of $G/e$ to the
equality of the corresponding invariants of $G$ and $G \setminus e$.
