You should not have the tenant’s car towed. Send the tenant a letter asking him to have this vehicle removed from the property. If that does not work, serve the tenant with a Form N5. The N5 gives the tenant an opportunity to correct the issue within a seven-day period after this notice is issued. If he does not comply with the N5, you can then apply to the Landlord and Tenant Board in order for the adjudicator to make a decision on this situation. You can obtain this form from the Board’s website at  https://tribunalsontario.ca/ltb/forms/