ECU location on a 2000 Mazda Prot?g?? - 2000 Mazda Protege

P0401 Exhaust Gas Recirculation Flow Insufficient Detected

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Most are on the back of the engine.

Back of engine.

No inertia switch on the Prot?g?. Ford thing. Not used by Mazda. No voltage to the Red with white stripe wire at fuel pump?

Should be look at both & see if they mount the same & if the wire harness is the same, might need a new ecu.

Did you use an impact to change the water pump? If you did not and reversed the rotation of the engine you bent a valve stem. Dohc has this quirk

1.6L (Zm) Engine Refer to the illustration for component location.

1. Loosen mounting bolts A, B and C.
   
2. Loosen the adjusting bolt D and remove the belt.
   

To install:

1. Installation is the reverse of removal.
   
2. Tighten mounting bolts A, B and C.
   

Location of the alternator mounting bolts and adjuster bolt D–Protégé 1.6L (ZM) engine


2.0L (Fs) Engine Refer to the illustration for component location.

1. Loosen mounting bolt A and B.
   
2. Loosen the adjusting bolt C and remove the belt.
   

To install:

1. Installation is the reverse of removal.
   
2. Adjust the belt deflection or tension by turning the adjusting bolt C.
   
3. Tighten mounting bolt A and B.
   

Alternator belt tension adjuster bolt (C)–Protégé 2.0 L (FS) engine

If you mean Engine Control Computer, look up behind glove box on passenger side.