Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
- CHECK IF TCM IS FLASHABLE NOTE: Controller is programmed with generic software and will not allow the correct vehicle Powertrain management.
- With the scan tool, record the vehicles controller part number.
- Select Use Controller Part Number under the Flash Tab.
- Flash the controller with the correct software.
Were you able to update (flash) the controller successfully?
Yes
- Test Complete.
- Perform NAG1 TRANSMISSION VERIFICATION TEST.
No
- Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM in accordance with the Service Information.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure .
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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