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 UnderbodyRemoval Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Disabling and Enabling.
Disconnect the negative battery cable. Refer to Bat ...
Front Side Door Trim Replacement
Front Side Door Pull Handle Bolt
Caution: Refer to Fastener Caution in the Preface section.
Tighten
2 N·m (18 lb in)
Front Side Door Inside Handle Bolt Finish Cap
Tip
Pull handle back to remove cap. Use suitable tool to unsnap.
Front Side Door Inside Handle Bolt
Tighten
...
Installation Procedure
Cut the roof front header panel in corresponding locations to fit the
remaining original panel. The sectioning joint should be trimmed
to allow a gap of one-and-one-half-times the metal thickness at the
sectioning joint.
Create a 50 mm (2 in) backing plate from the unused portion of ...