diff --git a/CalibPPS/TimingCalibration/plugins/PPSTimingCalibrationPCLHarvester.cc b/CalibPPS/TimingCalibration/plugins/PPSTimingCalibrationPCLHarvester.cc
index 6140fa15c5992..c75e2403a7568 100644
--- a/CalibPPS/TimingCalibration/plugins/PPSTimingCalibrationPCLHarvester.cc
+++ b/CalibPPS/TimingCalibration/plugins/PPSTimingCalibrationPCLHarvester.cc
@@ -42,6 +42,10 @@ class PPSTimingCalibrationPCLHarvester : public DQMEDHarvester {
   const std::string dqmDir_;
   const std::string formula_;
   const unsigned int min_entries_;
+  const double threshold_fraction_of_max_;
+  static constexpr double upper_limit_max_search_ = 20;
+  static constexpr double upper_limit_range_search_ = 20;
+  static constexpr double lower_limit_range_search_ = 8;
   static constexpr double resolution_ = 0.1;
   static constexpr double offset_ = 0.;
   TF1 interp_;
@@ -54,6 +58,7 @@ PPSTimingCalibrationPCLHarvester::PPSTimingCalibrationPCLHarvester(const edm::Pa
       dqmDir_(iConfig.getParameter<std::string>("dqmDir")),
       formula_(iConfig.getParameter<std::string>("formula")),
       min_entries_(iConfig.getParameter<unsigned int>("minEntries")),
+      threshold_fraction_of_max_(iConfig.getParameter<double>("thresholdFractionOfMax")),
       interp_("interp", formula_.c_str(), 10.5, 25.) {
   // first ensure DB output service is available
   edm::Service<cond::service::PoolDBOutputService> poolDbService;
@@ -123,7 +128,34 @@ void PPSTimingCalibrationPCLHarvester::dqmEndJob(DQMStore::IBooker& iBooker, DQM
           << min_entries_ << ". Skipping calibration.";
       continue;
     }
-    const double upper_tot_range = hists.toT[chid]->getMean() + 2.5;
+
+    //find max
+    int max_bin_pos = 1;
+    for (int i = 0; i < hists.toT[chid]->getNbinsX(); i++) {
+      double bin_value = hists.toT[chid]->getBinContent(i);
+      int bin_x_pos = hists.toT[chid]->getTH1()->GetXaxis()->GetBinCenter(i);
+      if (bin_x_pos > upper_limit_max_search_)
+        break;
+      if (bin_value > hists.toT[chid]->getBinContent(max_bin_pos))
+        max_bin_pos = i;
+    }
+    //find ranges
+    int upper_limit_pos = max_bin_pos;
+    int lower_limit_pos = max_bin_pos;
+    double threshold = threshold_fraction_of_max_ * hists.toT[chid]->getBinContent(max_bin_pos);
+    while (hists.toT[chid]->getTH1()->GetXaxis()->GetBinCenter(upper_limit_pos) < upper_limit_range_search_) {
+      upper_limit_pos++;
+      if (hists.toT[chid]->getBinContent(upper_limit_pos) < threshold)
+        break;
+    }
+    while (hists.toT[chid]->getTH1()->GetXaxis()->GetBinCenter(lower_limit_pos) > lower_limit_range_search_) {
+      lower_limit_pos--;
+      if (hists.toT[chid]->getBinContent(lower_limit_pos) < threshold)
+        break;
+    }
+    double upper_tot_range = hists.toT[chid]->getTH1()->GetXaxis()->GetBinCenter(upper_limit_pos);
+    double lower_tot_range = hists.toT[chid]->getTH1()->GetXaxis()->GetBinCenter(lower_limit_pos);
+
     {  // scope for x-profile
 
       std::string ch_name;
@@ -139,7 +171,7 @@ void PPSTimingCalibrationPCLHarvester::dqmEndJob(DQMStore::IBooker& iBooker, DQM
                             hists.toT[chid]->getMean(),
                             0.8,
                             hists.leadingTime[chid]->getMean() - hists.leadingTime[chid]->getRMS());
-      const auto& res = profile->getTProfile()->Fit(&interp_, "B+", "", 10.4, upper_tot_range);
+      const auto& res = profile->getTProfile()->Fit(&interp_, "B+", "", lower_tot_range, upper_tot_range);
       if (!(bool)res) {
         calib_params[key] = {
             interp_.GetParameter(0), interp_.GetParameter(1), interp_.GetParameter(2), interp_.GetParameter(3)};
@@ -170,6 +202,8 @@ void PPSTimingCalibrationPCLHarvester::fillDescriptions(edm::ConfigurationDescri
   desc.add<std::string>("formula", "[0]/(exp((x-[1])/[2])+1)+[3]")
       ->setComment("interpolation formula for the time walk component");
   desc.add<unsigned int>("minEntries", 100)->setComment("minimal number of hits to extract calibration");
+  desc.add<double>("thresholdFractionOfMax", 0.05)
+      ->setComment("threshold for TOT fit, defined as percent of max count in 1D TOT");
   descriptions.addWithDefaultLabel(desc);
 }