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Mazda
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2003
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MX-5 Miata Base, Standard
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Repair and Diagnosis
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Engine Performance
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System
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Engine Controls - Self-Diagnostics
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Diagnostic Tests
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DTC P1604: Code Word Unregistered In Pcm
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Possible Cause
Possible Cause
Immobilizer system reprogram procedure (key IDs) was not performed after replacing PCM.