The aim of the German Basic Law is to ensure a viable and stable government. As such, it actively blocks the willfull deselection of the Chancellor, unless he is replaced with a successor, and the willfull dissolution of parliament, unless the viability of the government is demonstratably impaired. Only the Chancellor is given the right to make that call, and he has to prove it via loosing a vote of confidence, and the Federal President has the right to not dissolve it even then.
In a 2005 decision (German text), the Federal Constitutional Court had to decide whether a vote of confidence called by Chancellor Schröder was constitutional.
The decision recounts the historical insights that lead to this design, if you are interested. For this answer, the general remarks on the nature of a "political crisis", and the "escape routes" the constitution offers, may suffice:
The Basic Law seeks to create a viable government by means of Article 63, Article 67 and Article 68. Viability means not only that the Federal Chancellor exercises political will in order to determine the general guidelines of policy, and that he bears responsibility for this (Article 65.1 of the Basic Law), but is also aware of having a majority of Members of the German Bundestag behind him in so doing (1.). The Basic Law contains special provisions in order to keep a minority government viable in a political crisis if necessary. Primarily, however, it offers escape routes aiming to restore stable majorities in the German Bundestag (2.)...
(1.) The constitution aims to create a government anchored in Parliament. The Federal Chancellor is elected by the Bundestag (Article 63 of the Basic Law). In order to effectively implement his mandate to shape policy thereby allotted, he requires the continuous support of the majority of the German Bundestag...
The Federal Chancellor and his Government need in principle a reliable parliamentary majority. Reliable means in this context that the Chancellor may anticipate fundamental, adequate parliamentary support for the political concept he represents...
(2.) If the Federal Chancellor is not (any longer) able to assemble the majority of Members of the Bundestag around himself, his position is categorised by the Basic Law as a political crisis and is covered by special provisions which also involve other constitutional bodies in the responsibility for dealing with it (Article 63.4 sentence 3 and Article 81 of the Basic Law; see also Article 111 of the Basic Law)...
However, these are only security measures. In principle, the Basic Law has available such ways out of a parliamentary crisis aiming to restore the majorities in the German Bundestag . These escape routes are the resignation and re-election of a Chancellor in accordance with Article 63 of the Basic Law, the election of a new, different chancellor by means of a constructive vote of no confidence in accordance with Article 67 of the Basic Law, and the vote of confidence in the Chancellor in accordance with Article 68 of the Basic Law...By its systematic connection with Article 62 and Article 67 of the Basic Law, Article 68 of the Basic Law however does not afford the Federal Chancellor any means to set a re-election date seeming suitable to him in a manner not subject to preconditions, together with a parliamentary majority reliably supporting him (BVerfGE 62, 1 (42-43)).
