Protege L4-1839cc 1.8L DOHC (1990)
Engine Control Module: Testing and Inspection
ECU Testing
The Mazda Engine Signal Monitor (#49 9200 162) is utilized to check ECU terminal voltages. This tool inspects individual terminal voltages as
selected with the monitor switch. A high impedance volt/ohm meter can also be used to check these voltages. Aftermarket test units are available that
will read ECU terminal voltages when connected with proper adapters.
To use the Engine Signal Monitor, connect unit between ECU and wiring harness with the correct adapter (#49 G018 903). Place pin number cover
sheet (#49 G018 904) on monitor face. Turn select and monitor switches to the desired terminal number for a voltage readout. Conduct tests with engine
at operating temperature unless instructed otherwise.
CAUTION:
Never apply voltage to terminals "A" and "B."
ECU TESTING PRECAUTIONS
1.
Never push circuit tester probes into connectors from ECU side.
2.
Before replacing an ECU, check components, wiring harnesses and terminal contacts if terminal voltage readings are incorrect. Repair as needed
and recheck voltage readings.
ECU PIN VOLTAGE CHART
Part 1
