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.
Flash Electrically Erasable Programmable Read Only Memory
The EEPROM is an integrated circuit (IC) within the PCM. This IC contains the software code required by the PCM to control the powertrain. One feature of the EEPROM is that it can be electrically erased and then reprogrammed without removing the PCM from the vehicle.
Manual data entry must be performed if the old module is damaged and/or incapable of communicating. Remove and replace the old PCM. Using the WDS or equivalent tester, select and execute module/parameter reprogramming referring to the manufacturers users manual. Important, make certain that all parameters are included. Failure to properly program tire size in revolutions per mile, (rev/mile = 63,360 divided by the tire circumference in inches) axle ratio, 4x4/4x2, and/or manual/electronic shift on the fly (MSOF/ESOF) may result in codes: P1635, and P1639.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.