Legacy Sedan 2WD F4-2.2L SOHC (1990)
Engine Control Module: Component Tests and General Diagnostics
ECU Power Supply And Ground Circuit
NOTE: Never connect or disconnect the control unit or any sensors with the ignition "ON" unless specifically instructed to do so by a test
procedure. Failure to follow this precaution could result in damage to electronic components.
While there is no specific test for the ECU, nor does it set a trouble code if a fault occurs in its own circuitry, many of the component tests lead to the
control unit if no other problems are detected.
Apparent ECU problems can result from power supply and ground circuit problems. Therefore, these should be checked if a faulty ECU is suspected.
ECU POWER SUPPLY CHECK
ECU Ground Circuit Check