- If the DTC exists, diagnose the applicable DTC. (See DTC TABLE.)
- If the DTC does not exist, MIL does not illuminate, and HOLD indicator light flashes, diagnose the applicable symptom troubleshooting. (See SYMPTOM TROUBLESHOOTING ITEM TABLE.)

* :Malfunction indicator lamp (MIL), HOLD indicator light
Automatic transaxle on-board diagnostic functionMazda 6 Service Manual: Dual proportioning valve replacement (without abs)
1. Remove in the order indicated in the table.
2. Install in the reverse order of removal.
Dual Proportioning Valve Installation Note
Install the dual proportioning valve so that the R mark faces the left side
of the vehicle.
...
Mazda 6 Service Manual: No.2 amount of air blown from vents does not change
Full-auto Air Conditioner
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while performing the inspection to discover
whether poor contact points are the cause of any intermittent malfunctions.
If there is a problem, check to mak ...