Mazda MX-5 Miata Sport 2007 Manual page 2062

2007 ENGINE PERFORMANCE Symptom Troubleshooting - MX-5 Miata
Fig. 14: IAT Sensor & ECT Sensor - Circuit Diagram
Courtesy of MAZDA MOTORS CORP.
Input Signal System Inspection For Thermistor Type
1. When an irregular signal is detected, measure the #1 PCM terminal voltage.
If the #1 terminal voltage and the M-MDS or equivalent monitor voltage are the same, proceed to

the next step.
If there is a difference of 0.5 V or more , inspect the following points concerning the PCM

connector:
Female terminal opening loose

Coupler (pin holder) damage

Pin discoloration (blackness)

Harness/pin crimp is loose or disconnected.

2. Measure the #2 sensor terminal voltage.
If there is a 0.5 V or more difference between the sensor and the M-MDS or equivalent voltages,

inspect the wiring harness for open or short circuits.
If the sensor and the M-MDS or equivalent voltages are the same, inspect the following points

concerning the sensor connector:
Female terminal opening is loose.

Coupler (pin holder) damage

2007 Mazda MX-5 Miata Sport