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Home >> Mazda >> 1997 >> Protege ES L4-1839cc 1.8L DOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Relays and Modules - Computers and Control Systems >> Engine Control Module >> Testing and Inspection >> Using Engine Signal Monitor

Using Engine Signal Monitor

CAUTION: The PCM terminal voltages vary with change in measuring conditions and vehicle conditions. Always carry out a total inspection of the input systems, output systems, and PCM to determine the cause of trouble. Otherwise, a wrong diagnosis will be made.

1. Disconnect the negative battery cable.
2. Remove the rear console, front console and undercover.
3. Disconnect the PCM connector.
4. Connect the Special Service Tool (Harness Adapter) to the PCM connector.




5. Connect the Special Service Tools (Engine Signal Monitor and Harness adapter, power) to the Special Service Tool (Harness adapter). Use connector A of the adapter harness for PCM terminals 1A through 1V and 3A through 3R Use connector B for PCM terminals 2A through 2L and 4A through 4Z.




6. Place the Special Service Tool (Sheet) on the Special Service Tool (Engine Signal Monitor).
7. Measure the voltage at each PCM terminal by switching the selector switch and the monitor switch.
8. If any incorrect voltage is detected, check related systems, wiring harnesses and connectors referring to the possible malfunction in the terminal voltage list.

CAUTION:
- Disconnecting the connectors of the PCM and the Special Service Tool (Adapter harness) while the battery is connected can damage the PCM and the Engine Signal Monitor. Disconnect the negative battery cable and the Special Service Tool (Harness adapter, power) before disconnecting the connectors.
- Applying voltage to terminals A and B of the Special Service Tool (Engine Signal Monitor) can damage the Engine Signal Monitor.




NOTE:
- The indicator lights of the Special Service Tool (Engine Signal Monitor), provided for confirmation of the voltmeter range, is also used for detection of the pulse such as the fuel injector control signal, which is difficult to detect by using the voltmeter.
- Terminals A and B of the Special Service Tool (Engine Signal Monitor) are for connection of an external instrument. By connecting an external instrument such as a circuit tester or an oscilloscope, various inspections in addition to the measurement of the PCM terminal voltages are made possible.
















Terminal Voltage Reference Charts

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