When spoken to by police he said he had "no control over what he did", the court heard.
Ten days later, Pearce was waiting outside his partner's children's school.
As she dropped them off he "yanked open" the rear driver's side door and tried to remove their two-year-old daughter from her carseat as he demanded the other children get out of the car, Mr Wilson said.
Climbing into the front passenger's seat he began yelling at his former partner, accusing her of having an affair, the sergeant told the court.
He then got out of the car and removed the child from her carseat as the woman pleaded for him to put her back as she was ill.
Before trying to grab the car keys from the ignition, he got back into the car yelling at the woman.
The victim pushed him away and as she drove away he followed in his car until he saw her on her mobile phone.
Lawyer Virginia Pearson told the court plans were underway to get him on a programme.
Judge Walsh told him if he breached the protection order again there would be little choice but a remand in jail.
"You need to understand the court has concerns about breaches of protection orders. This order is a serious order.
"If you breach it there are consequences. You will find yourself in custody," he told Pearce.
Pearce was remanded on bail to a Foxton address for a pre-sentence report and sentencing on September 26.
