My vehicle doe not have power - 2000 Isuzu Rodeo

It mean the electronics in the vehicle has put a limit on how much of the power the engine has. 'Reduced Engine Power' means you are only getting some of the power the engine has. Do you have any warning lights on your dashboard?
This usually happens because the vehicle has found a fault in the system it thinks is serious, reducing the power to prevent damage. Take the vehicle to a Good mechanic and they will be able to tell you why it is happening.
Please comment below if I can give you any more help.

I understand. What is year--make--model? If your vehicle is sold in the US, I'll try to look up power distribution diagram for your vehicle, hopefully, it will show which fuse does what?

A factory or a professional scan tool would be a great help in diagnosing this problem ! The PCM - engine computer supplies a ground to the injectors if all the right inputs to the PCM are there ! Crankshaft position & Camshaft position sensors being the most important . Plus if there was an anti-theft system problem , in most vehicles ,the injectors would be disabled ! Does the check engine light come on when you turn the key on , not to start , just on ? Does your vehicle have a Tachometer ? When cranking the engine does the tachometer move ? Also is there spark ? Did you pull a plug wire an hold near metal on the engine while someone else cranked the engine ? Check for power an grounds at the PCM , no power , check the ASD relay ! The ASD relay powers up the vehicle an they do go bad ! short inside or open circuit etc...

What makes a buzzing sound , the door lock actuators ? Or where do you hear the buzzing coming from if not at the doors ?
Power Lock
The power lock/unlock feature requests all of the vehicle doors, including the liftgate, be locked or unlocked upon a customer request from any interior door lock switch in the vehicle. The power door locking system functions independently of ignition status or vehicle speed. When the vehicle security module receives an unlock/lock command from any door lock control switch, the vehicle security module will activate relays internal to the module to supply the correct power and grounds for the door lock actuators.
Visual Inspection Chart Mechanical Electrical

• Binding latches

• Central junction box (CJB) fuse(s):
  • 5 (7.5A)
  • 30 (30A)
• Circuitry
• Relays
• Remote transmitter
• Keyless entry keypad
• Vehicle security module

1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

1. If the diagnostic tool does not power up, refer to the diagnostic tool manual.
1. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
   • SCP, UBP or ISO; all elctrconic control unitw, no response/not equipped, refer to Section 418-00 .
   • No response, not equipped for vehicle security module, refer to Section 419-10 .
   • System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs, and carry out the self-test diagnostics for the vehicle security module.
2. 1. If the DTCs retrieved are related to the concern, go to the Vehicle Security Module Diagnostic Trouble Code (DTC) Index to continue diagnostics.
   1. If DTCs are retrieved that are not found in the following Vehicle Security Module Diagnostic Trouble Code (DTC) Index, refer to the Master Vehicle Security Module Diagnostic Trouble Code (DTC) Index in Section 419-10 .
   1. If no DTCs related to the concern are retrieved, proceed to the Symptom Chart to continue diagnostics.

What make vehicle do you have ? model an year too ? Some newer vehicles , an I mean from 96 on have relays that power up some systems on the vehicle , like ford has a power hold relay an GM has run/crank relay an Chrysler has ASD relay . Foreign vehicles have them too . You need to get a power distribution diagram for your vehicle an see where there power comes from ! You can get it here www.bbbind.com free wiring diagrams ! click on technical information , next page click on tsb's an wiring diagrams . The bottom of the next page click on I agree . Next page click wiring diagrams an then enter your vehicle info . in system click power distribution ! Good luck ,hope this helps an God bless !

What make model an year vehicle ? any messages on dash - REDUCED ENGINE POWER ? check engine light ? Does the vehicle have electronic throttle control ?

Some have internal fuses some have a fuse on the back if you have wired the battery incorrect and the radio was connected to the battery terminals you have probably fried the stereo.

The power steering on your 2005 Chevrolet Malibu Maxx has electronic power-assist and not hydraulic power-assist so there is no hydraulic fluid. If you're not already aware, this vehicle is part of a major recall from General Motors for power steering failure. Contact your local Chevrolet dealership for more information. You will need your vehicles VIN as shown on your registration or dash plaque. Hope this helps.

Does the vehicle start an run ? If it does ,the brain as you call it is working fine . The check engine light has nothing to do with the PCM /ECM sensing problems .You probably should take your vehicle to a qualified repair shop .

Many of these vehicles have a power button by the shifter. It gives extra boost when going up hills or towing Then when it's off, it puts the vehicle in economy gas saving, power saving mode.