General Motors in the US has become the latest car maker to call on accident repairers to carry out complete vehicle diagnostic scans both before and after repairs. Honda and Toyota have also made similar moves recently.

Manufacturer directions on scanning has been a matter of great debate in America in recent months and more car makers recommend repairers thoroughly investigate diagnostic trouble codes that may be caused by accident damage.

GM says its goal is to ensure that all necessary repairs are diagnosed during the estimate process, and that vehicles are returned to customers in pre-crash condition. It also points out that testing is especially critical when safety systems are impacted and these can be impacted by even slight damage and that post accident testing is important when electrical systems are disconnected during repairs.

The position of the car makers raises issues around diagnostic equipment investment and training, with some independents saying it is just a means to drive repairs back to dealers. Concerns have also been raised about the reluctance of some insurers to pay for the required additional labour time.