Nissan is making a new safety pitch in ads breaking this week as part of a larger marketing overhaul that will take full effect in June.

The changes come after much soul searching among Nissan marketing and sales leaders and its agencies as the automaker in recent months studied how to improve its brand positioning. The process was sometimes painful, as evidenced by recent comments made by new U.S. sales boss Christian Meunier. In a recent interview with Automotive News, he critiqued the Nissan brand as "vague" despite billions of dollars spent on ads in recent years.

"I was really upset with the agency in the beginning," Mr. Meunier told Automotive News during the New York auto show in March. Nissan's advertising is handled by a dedicated Omnicom unit known as Nissan United that includes TBWAChiatDay, Zimmerman Advertising, OMD and other Omnicom agencies. "I challenged them. I locked them in a room for a week in New York, and came back after a week and it was still shit. … I came back after two weeks and it was still shit," Mr. Meunier said. "I said, 'You guys better deliver something. You'd better come to Nashville next week with a plan that works.' And they came back with a very good plan."

That plan will begin rolling out this week via so-called Tier 2 advertising that will promote a national sales event but be tailored to dealerships in individual markets. A broader brand campaign will break in June in which the new strategy will come into full view. The Tier 2 ads promote technology-fueled safety features such as predictive forward collision warning and blind spot warning.

A spot breaking this week (above) by Zimmerman called "Safety Today" features people who treat auto accident victims, such as firefighters, emergency medical technicians, police officers and nurses. They are given an up-close view of how Nissan safety features can prevent accidents and their positive reactions are shown in the ad.

"Safety doesn't have to be boring. And that was part of the brief that I gave the team," said Jeremy Tucker, Nissan North America's VP for marketing, communications and media. "How do you make safety compelling and exciting and give it some punch."

Nissan has historically shied away from such messaging because "we thought the brand DNA and safety didn't match," Mr. Tucker added. But the the "advanced driver assistance system that we have in our cars can help prevent 30% of [auto] crashes," he said, citing research and analysis from The Boston Consulting Group. And as that idea was presented to consumer focus groups, "there was a lightbulb that went off," he said. "It got them to understand that this is what a new car can offer."

Safety will also be a key message in the bigger brand campaign launching in June. But the campaign -- which will keep Nissan's "Innovation That Excites" tagline -- will also plug at least two more attributes, Mr. Tucker said without naming them. "Safety is one of the things people seek and there are many other things they look for and this new campaign will articulate what consumers are looking for in their lives."

Mitch Hershey, Zimmerman's executive VP for the Nissan division, said the safety message will be used for ads about sedans, while the marketing planned for crossovers "has much more to do with capability."

The safety ads come in the wake of a Friday announcement in which Nissan said it was recalling 3.53 million vehicles worldwide, including nearly 3.2 million in the U.S., because of a potential airbag deployment issue. Asked if that issue would affect the safety ads, Nissan said in a statement that "it's two different topics. The Safety Today event focuses on advanced safety technologies in Nissan vehicles and educates consumers about the important benefit of active safety. The unrelated safety recall is a precautionary measure to remedy a potential defect to ensure the safety of our customers."

The goal of the marketing changes is to better unite the dealer-focused Tier 2 ads with bigger brand campaigns, which are known as Tier 1. "Tier 1 and Tier 2 historically have been a little bit opposed. They now have one voice and one shared purpose for Nissan," Mr. Tucker said.

Nissan leaders have also demanded greater teamwork among the individual agencies that comprise Nissan United. All the shops are now briefed together on big ideas, for instance. "I demand collaboration," Mr. Tucker said.

The changes are occurring under a relatively new leadership team. Mr. Tucker joined Nissan in September 2014 as an automotive outsider, having previously held roles at Disney Consumer Products and Frito-Lay. Mr. Meunier, who is Mr. Tucker's boss, is a 14-year veteran of Nissan, but is new to his current role. He became senior-VP of sales and marketing and operations in January. He was marketing VP for Nissan North America from 2007 to 2010.

"It was a big stick that Christian brought, but I can tell you that the team has risen to the challenge," Mr. Tucker said, referring to the views expressed to Automotive News. "That statement removed all the egos from the room," he added. It "galvanized the entire team against one mission because we made up our minds … that we are aligned and that we are not going to fail."

Mr. Hershey, who has worked on Nissan for many years at Zimmerman, said Mr. Meunier "clears away the fluff and has laser focus" and "wants consistency in messaging."

As Nissan leaders plotted their new strategy, they considered changing agencies, Mr. Tucker said, but decided to to stick with Omnicom's Nissan United. "It's very easy to do an agency review if you don't want to have tough conversations," he said. But "we had the tough conversations and then we aligned everyone."

Even so, Nissan leaders helped orchestrate changes in Nissan United's leadership. Late last year, for instance, TBWA\Chiat\Day appointed Andrew Dauska as managing director of the agency's Nissan account. He joined from Wunderman in Minneapolis and has experience working on brands including Subaru and Porsche.

It is not as if Nissan is slumping. Nissan North America in March posted its biggest sales month ever, selling 163,559 cars and trucks, Automotive News reported.

But the automaker wants to keep growing its market share. Through March, Nissan North America had 9.8% U.S. market share, including Infiniti sales, according to Automotive News. "We want 10% market share," Mr. Tucker said. "We want to really start dominating some of these conversations. It requires us to be much, much more strategic and much, much more aggressive. And that's why the marketing matters so much right now."

On the media side, Nissan, under Mr. Tucker, has adopted a "go big" strategy that targets big moments such as sponsoring the College Football Playoff. That is now being complemented with an aggressive shift to more digital advertising. The goal is 40% digital spend, up from recent percentages in the high 20s and low 30s, Mr. Tucker said.