Dave Lewis was speaking after the supermarket chain revealed its latest results and the conclusions of an inquiry into an accounting scandal.
Its chairman Sir Richard Broadbent confirmed a plan to quit as the probe identified a £263m profit overstatement.
Tesco said the internal investigation by Deloitte into its procedures had found historic failures in its UK food business going back a number of years, having previously suggested the error was a one-off.
The overstatement reflected profits in previous reporting periods too, Tesco confirmed, not just in the first half of its financial year.
Its share price fell 7% when the FTSE 100 opened for business in the wake of the statement but later eased back.
Analysts said it could be explained by UK sales continuing to fall and Mr Lewis' decision not to launch an immediate discount challenge to rivals - especially hard discounters at the bottom and Waitrose at the top end, who have eaten away at its market share.
Mr Lewis told Sky's Business Presenter Ian King: "Our promotional intensity is very high."
He said: "The critical thing is that I and 320,000 other people give great service, make sure everything's available in a really good, quality way, and then price will be part of the equation."
But he added he might think about price in a "different way" once his business review was completed.
Thursday's results statement was delayed by a month because of the investigation.
Eight senior executives have been suspended pending the outcome of the inquiry, which examined how Tesco logged suppliers' rebates and if they were reported in the correct accounting period.
Tesco said there was no evidence anyone at Tesco had sought to gain personally but the findings raise questions about the leadership of former chief executive Philip Clarke (Toronto: CKI.TO - news) , who stepped down in the summer before the accounting issues were made public.
Tesco said his pay-off - and that of former finance chief Laurie McIlwee - was being delayed until such time as inquiries were complete.
Sir Richard said his decision to stand down reflected "the important principle of accountability."
The accounting scandal failed to overshadow the spotlight on Tesco's turnaround efforts.
Pre-tax profits fell 92% to £112m in its first six months while UK trading profit was down 55.9% to £499m.
UK like-for-like sales were 4.6% lower - slightly better than expected.
Mr Lewis said: "We know that we have got a lot of work to do.
"We know what it is we need to do to turn the business around ".
Tesco's market value - which has lost £17.6bn in the last five years - has plunged more than 50% in the past 12 months alone.