Yes. You are reffering to the Pension Adjustment (PA) which is a applied for both private and public defined-benefit pension plans and reduces the RRSP contribution limit. The PA calculation depends on the specifics on the pension plan. Your pension formula determines what is called the accrued benefit that determines the PA. You can ask your pension provider for what that is. For most public pensions, it is 2% (the max), and we ask you for that when you enter or edit a pension income. You must make sure to click Submit on the the Add/Edit income form, and if the income is a DB Pension it will then ask you for specifics on that pension including:
Percent of salary accrued benefit per year, usually close to 2 (percent), check your pension formula
If you don't know, enter 2. The TIME MACHINE does calculate the PA given that and reduces the contribution room automatically.
That form also asks you for the salary it is linked to if you are still contributing to the pension, and you would have to have entered that as a seperate income previously. Other inputs on that form are for calculations of survivor benefits, and for estimating a commuted value (although that is only a gross estimate, only your pension provided knows for sure).