Mazda CX-9 Grand Touring 2009 Manual page 1395

If it is at 0 V , inspect the sensor. If necessary, replace the sensor.
If not, inspect for the following:
Open circuit in wiring harness
Female terminal opening is loose.
Coupler (pin holder) damage
Pin discoloration (blackness)
Harness/pin crimp is loose or disconnected.
MAIN RELAY OPERATION INSPECTION
1. Verify that the main relay clicks when the ignition switch is turned to ON position and off.
If there is no operation sound, inspect the following:
Main relay (See RELAY INSPECTION .)
Harness and connector between battery and main relay terminal A.
Harness and connector between PCM terminal 1Q and main relay terminal E.
ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION
Engine coolant temperature compensation inspection
1. Connect the M-MDS to the DLC-2.
2. Access the following PIDs:
ECT
IAT
RPM
3. Verify that the engine is cold, then start the engine.
4. Verify that the engine speed decreases as the engine warms up.
If the engine speed does not decrease or decreases slowly, inspect the following:
CHT sensor and related wiring harness
(See CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI-
3.7] .)
Electronic throttle body and related wiring harness
(See THROTTLE BODY INSPECTION [MZI-3.7] .)
Load compensation inspection
1. Start the engine and idle it.
2. Connect the M-MDS to the DLC-2.
2008 Mazda CX-9 Grand Touring
2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9