Function inspection

WARNING: This page is about a different car, the 2021 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

Connect the M-MDS to the DLC-2.
Switch the ignition ON (engine off).
Display the PCM PID [ECT_VOLT] and [ECT]. (See PID/DATA MONITOR INSPECTION .)
Compare the voltage indications for PID [ECT_VOLT] and the temperature indications for PID [ECT] with the standards in the table indicated below.

If they do not match the standard, replace the PCM. (See PCM REMOVAL/INSTALLATION .)
If they match the standard, perform the resistance inspection. (See RESISTANCE INSPECTION .)

STANDARD VOLTAGE SPECIFICATION

ECT_VOLT	ECT
V	°C {°F}
Approx. 3.10	20 {68}
Approx. 2.16	40 {104}
Approx. 1.40	60 {140}
Approx. 0.87	80 {176}
Approx. 0.54	100 {212}