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.
DTC P1602: Pcm Not Programmed: Testing
Attempt to program PCM. See PROGRAMMING . Start the engine. If the engine will not start, crank the engine over for 15 seconds. Crank at least 2 times with the ignition switch returning to the off position each time. Allow the engine to reach normal operating temperature. With the DRBIII®, read DTCs. Does the DTC reset? If yes, replace and program the PCM. See PROGRAMMING . Perform POWERTRAIN VERIFICATION TEST VER-1 under VERIFICATION TESTS. If no, test is complete.
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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.