Engine Control Module Self Test: Description

The ECM performs a number of self-test integrity diagnostics on its internal hardware and software to check for faults. An error is detected if the ECM receives no CAN messages for at least 0.8 seconds, the calculated checksums at power down do not match the values stored in flash Electrically Erasable Programmable Read Only Memory (EEPROM) or the internal or external RAM fails a read/write test. For engine control module self test testing, see Fig 1 .

Fig 1: Engine Control Module Self Test DTC Testing

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