what all can go wrong when your ecu is bad?
The ECU is the Engine Control Unit -- Anything that it controls ( every aspect of the engine operation and driveability of the vehicle ) can be affected depending on what part of the ECU is bad ( think of it as a human brain, of sorts. If the part of the brain that controls speech is damaged, you could still have sight and still live and function but you wouldn't be able to speak. Also, like the brain, if the part that actually controls your heart or breathing, you would not live. Likewise, with the engine ECU, the car would not run ). There are no serviceable parts to the ECU, if it is "bad" it must almost always be replaced.
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