A vehicle testing system and method includes a vehicle testing system that is operatively connected with a vehicle computer whereby the system is able to evaluate signals within the vehicle computer. The system includes a tamper testing sequence for detecting vehicle tampering comprising applying a test action to the vehicle intended to generate a signal in the vehicle computer responsive to the test action, monitoring the signal of the vehicle computer associated with the test action, and determining whether the signal meets an expected response. A determination that the signal of the vehicle computer associated with the test action does not meet the expected response indicates that tampering has occurred.