Caterpillar — Welding on Engines with Electronic Controls
Repair & overhaul · engine ECM and electrical system
From a Caterpillar owner's manual covering: 3306B, 3406, 3406E, 3412C, 3412C Generator Set, 3500 Series. Check it applies to your exact model before use.
Applies to: Caterpillar 3306B, Caterpillar 3406, Caterpillar 3406E, Caterpillar 3412C, Caterpillar 3412C engine
Before you start
- Do not ground the welder to electrical components such as the ECM or sensors.
Procedure
- Stop the engine; turn switched power to OFF.
- Disconnect the negative battery cable; open battery disconnect switch if provided.
- Disconnect J1/P1 and J2/P2 connectors from the ECM.
- Disconnect any component with a microprocessor from the engine harness.
- Connect welding ground cable directly to the part being welded, close to the weld.
- Protect the wiring harness from welding debris and spatter.
- Use standard welding practices to weld the materials.
Specs & values
- Do not ground the welder across the centerline of the package
Full service-parts list: Caterpillar 3406 →, Caterpillar 3406E →, Caterpillar 3412C →, Caterpillar 3412C engine →
Source: Caterpillar owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.