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.

2006 Mazda MPV ESFACTORY OEM SERVICE PROCEDURE

DTC P1621: Notes

DTC P1621 [AJ] DETECTION CONDITION AND POSSIBLE CAUSES

DTC P1621	Code word does not match after engine cranking
DETECTION CONDITION	Code word stored in PCM and immobilizer control module do not match
POSSIBLE CAUSE	Immobilizer system reprogram procedure (code word) was not performed correctly after replacing immobilizer control module or PCM.

Factory Service Tools

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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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