1. Remove the VAD control solenoid valve. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.)
2. Inspect airflow between the ports under the following conditions.


Circuit Open/Short Inspection
1. Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION.)
2. Inspect the following wiring harness for open or short (continuity check).

Open circuit
- VAD control solenoid valve terminal B (harness-side) and PCM terminal 4C
- VAD control solenoid valve terminal A (harness-side) and main relay terminal C (harness-side)
Short circuit
- VAD control solenoid valve terminal B (harness-side) and body GND
- VAD control solenoid valve terminal A (harness-side) and power supply
Variable air duct (vad) shutter valve inspection (l3)
Variable air duct (vad) check valve (one-way) inspection (l3)Mazda 6 Service Manual: Starting a Flooded Engine
If the engine fails to start, it may be flooded (excessive fuel in the engine).
Follow this procedure:
1. If the engine does not start within five seconds on the first try, wait ten
seconds and try again.
2. Make sure the parking brake is on.
3. Depress the accelerator all the way and hold it ...
Mazda 6 Service Manual: Heater core inspection
1. Remove the A/C unit. (See A/C UNIT REMOVAL/INSTALLATION.)
2. Remove the heater core from the A/C unit.
3. Inspect for cracks, damage, and coolant leakage.
If any problems are found, replace the heater core.
4. Inspect for bent fins.
If any are bent, use a flathead screwdriver to stra ...