This information provides repair recommendations and general guidelines for steel classified as Ultra High Strength Dual Phase Steel (Dual Phase Steel with a tensile strength greater than 800 MPa), also known as DPX.
General Motors recommends the following when repairing or replacing this type of steel during collision repair.
Note:
Recommended Repairs:
Special Tools and Equipment

Mild Steel
Frame and UnderbodyCollision Repair
Specifications
Point-to-point measurements are for reference only. All measurements are
given in millimeters. Use these measurements for diagnosing
and estimating. Point-to-point measurements are duplicated with tram bar
pointers set at equal lengths. All die marks, holes, slots, and
fast ...
Installation Procedure
Note: If the location of the original plug weld holes can
not be determined, space the plug weld holes every 40 mm (1½ in).
Drill 8 mm (5/16 in) for plug welding along the edges of the underbody
rear side rail reinforcement as noted from
the original panel.
Clean and ...
New Vehicle Break-In
Notice: The vehicle does not need an elaborate break-in. But it will
perform better in the long run if you follow these guidelines:
• Do not drive at any one constant speed, fast or slow, for the first 805 km (500
mi).
Do not make full-throttle starts. Avoid downshifting to brake or slow the v ...