Your PCM, ECU, or ECM controls nearly every performance function in your vehicle. When it begins to fail, symptoms can appear random or misleading.
Here are the top 10 warning signs:
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Persistent Check Engine Light that will not clear
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Engine cranks but will not start
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Random or multiple cylinder misfires
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Poor fuel economy
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Transmission shifting problems
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Vehicle stalls randomly
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Loss of communication with scan tool
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Failed emissions test
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Erratic electrical behavior
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Burned or corroded PCM connectors
Common causes of engine computer failure include heat exposure, voltage spikes during jump-starting, weak batteries or alternators, shorted ignition coils, water intrusion, and aging internal components.
Proper diagnosis is critical before replacement. However, when confirmed, installing a properly programmed replacement PCM often restores full vehicle function immediately.
