Engine speed input circuit malfunction
Diagnostic Support Notes
If this code appears with P0335, perform diagnostic on the crankshaft position sensor circuit, clear trouble codes and verify repair. Otherwise, inspect the connectors and wiring between the engine control unit and transmission control module for damage, open circuits, and shorts. Clear any stored codes and verify repair. If P0725 persists, replace the transmission control module. If P0725 still persists, replace the engine control unit. *See notes.
[P0725 - From 2002 Mazda Millenia factory service manual]
Notes: Engine stall that occurs while cruising, caused by timing belt breakage/slippage, ignition system failure, or even running out of fuel, may store a P0725 code after the stall event. If the engine now turns over but will not start and the only code stored is P0725, see Symptom Troubleshooting #6 - Cranks normally but will not start.