A search for the standard model Higgs boson produced in association with a top quark pair is presented, using 2.3 /fb of 13 TeV pp collision data collected by the CMS experiment at the CERN LHC. Final states with a Higgs boson that decays to either ZZ,WW, or ττ are required to have a top quark pair that decays to either lepton plus jets (tt → lνjjbb) or dileptons (tt → lνlνbb), where l represents an electron or a muon. The following signatures are selected: two isolated same-sign leptons (electrons or muons) plus b-tagged jets, three isolated leptons plus b-tagged jets, or four isolated leptons plus b-tagged jets. The presence of an hadronic τ reconstructed in the event is also considered in the event categorization. The expected 95% confidence level upper limit on the Higgs boson production cross section for a Higgs boson mass of 125 GeV is 2.6 times the standard model expectation, compared to an observed limit of 3.5. The signal strength µ, relative to the expectation for the standard model Higgs boson, is measured to be 0.8^(+1.4)_(-1.2).