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a flashing 'D4 ' light means a fault with the transmisson
which can prevent the engine from cranking but the most likley source is a faulty 'main' relay thats called out in the fuse box as the PGFM unit
Its a large multipurpose unit that runs the ECU, transmisson controller and a few others so I'd suggest to pull that out and replace it
do you still need help?
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