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Ron Z.
Ron Z., - Chevy Tech -
Category: Chevy
Satisfied Customers: 18866
Experience:  18+yrs experience. State Inspector and Chevy Diagnostics
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My 2005 chev Impala has a code P O 128 what to look for, how to fix?

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my 2005 chev Impala has a code P O 128 what to look for, how to fix?

The most common fail item associated with the P0128 is a faulty ECT (Engine Coolant Temp) Sensor.


If you can double check your engine size (Impala was not offered with a 3.5L in 2005. Either 3.4L or 3.8L) I can get you a location and replacement procedure.


Customer: replied 6 years ago.

ok, 3.8L


  • Partially drain the cooling system.
  • Remove the thermostat housing.
  • Disconnect the ECT sensor electrical connector.
  • Remove the ECT sensor.
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