Hank was attempting to persuade Nick to buy a new car. The Grimm's Toyota Land Cruiser was essentially the opposite of cool. Hank decided since Nick had a detective's salary now, instead of the salary of a cop, he could afford some nicer wheels.
With Hank nagging him constantly at work, Nick agreed to check out a car.
His partner looked dismayed when he showed up the next day in his old Toyota. "What was wrong with the Lexus?" Hank asked when Nick sat down at his desk. Nick shrugged and replied, "Nothing really, but it's not my car." Hank rolled his eyes but did not bring the subject up again.