OEM Repair Procedures and Documentation for Welded Repairs

Why OEM Repair Procedures Control Every Weld You Make

When a vehicle leaves the factory, its structural integrity depends on exact weld types, locations, quantities, and joint designs chosen by the manufacturer's engineers. After a collision, reproducing that structure correctly is your legal and professional obligation. Original Equipment Manufacturer (OEM) repair procedures are the authoritative source that tells you how to do that. Using an outdated general guide or guessing at specifications is never acceptable on a structural repair — it can produce a vehicle that fails in a subsequent crash.

Every major manufacturer publishes model-specific repair information. Platforms such as OEM1Stop, I-CAR's Repairability Technical Support (RTS) portal, and individual manufacturer portals (for example, GM's OPS, Ford's OASIS, Toyota's TIS, and Honda's iN) deliver this information. Your school provides access to a demonstration account. Always confirm you are reading the procedure for the exact year, make, model, and trim level, because specifications can change between model years — even mid-year.

What OEM Procedures Tell You About Welded Repairs

A structural repair section in an OEM procedure typically specifies:

• Weld type — for example, MIG plug weld, squeeze-type resistance spot weld (STRSW), or MIG continuous weld
• Number and location of welds — often shown on an exploded diagram with callouts
• Steel grade — such as mild steel, high-strength steel (HSS), advanced high-strength steel (AHSS), or ultra-high-strength steel (UHSS). The grade determines whether you can apply heat, what wire and gas you must use, and whether STRSW is required instead of MIG
• Prohibited operations — some AHSS and UHSS panels must not be straightened with heat; some require STRSW only and prohibit MIG welding entirely because heat alters the material's engineered properties
• Wire and shielding gas specifications — the OEM will specify wire diameter and, for MIG, the shielding gas mixture. A common specification for steel is ER70S-6 wire with a 75% Argon / 25% CO₂ (C25) mixture, but always verify; never assume
• Post-weld corrosion protection — bare metal created by welding must be treated immediately. OEM procedures specify primer type, cavity wax, and seam sealer products and locations

Completing a Repair Order That Captures OEM Requirements

A repair order (RO) is not just a billing document — in collision repair it is the technical record of how the vehicle was fixed. For a welded structural repair, a compliant RO must capture all specifications so that anyone reviewing the file — an insurer, a quality auditor, or a future technician — can verify the repair met OEM standards.

For this lesson, your RO must contain eight required fields:

1. OEM source — name of the platform and the specific document/page you used

2. Steel grade — as stated in the OEM procedure

3. Joint type — butt, lap, or flange, as specified

4. Weld process — MIG plug, MIG continuous, or STRSW

5. Wire specification — diameter and AWS classification

6. Shielding gas specification — mixture and flow rate if stated

7. Weld quantity and location — number of welds and where they are placed on the panel

8. Corrosion protection step — products and sequence required after welding

Leave nothing blank. If the OEM procedure does not specify a field, note "not specified — see OEM source" so reviewers know you checked.

Prohibited Operations and Safety Implications

Before you weld a single inch, confirm the OEM procedure does not prohibit your planned process on that panel. Applying an open-arc MIG weld to a panel that requires STRSW can overheat AHSS and destroy its tensile properties, weakening the structure below original design. This is a recognized safety risk documented by I-CAR and vehicle manufacturers.

PPE and shop safety apply regardless of the welding process:

• Wear a properly rated auto-darkening welding helmet, leather gloves, and flame-resistant clothing.
• Ensure adequate ventilation or use approved respiratory protection — coated or primed metals produce hazardous fumes.
• Disconnect the vehicle's 12-volt battery and any hybrid/EV high-voltage system per OEM instructions before welding near electronic modules. Follow your shop's lockout/tagout procedure for high-voltage vehicles.
• Remove fuel lines, brake lines, and wiring harnesses from the immediate weld area or protect them with appropriate heat shielding.
• Keep a fire extinguisher rated for your shop's hazards within reach.

Peer Review and Documentation Quality

Peer review is standard practice in professional shops. A second technician checking documentation catches errors before the vehicle leaves — not after. When reviewing a partner's RO, use the checklist systematically: verify each of the eight fields against the OEM source they cited, not your own memory. Note the exact field that is missing or incorrect and be specific. "Gas spec says 100% Argon but OEM requires C25" is a useful finding; "gas is wrong" is not.

Accurate documentation supports both credential requirements. I-CAR ProLevel coursework emphasizes following OEM repair procedures as a core competency. ASE B-series testing expects technicians to understand weld processes, material identification, and corrosion protection — all of which begin with reading and applying OEM specifications correctly.