Without Using the M-MDS

1. Disconnect the OCV for hydraulic variable valve timing system connector.
2. Start the engine and idle it.
   NOTE:

   • When applying battery voltage between the OCV for hydraulic variable valve timing system terminals, the positive and negative cables can be connected to either terminal A or B.
3. Verify that the engine idles roughly or stalls when battery voltage is applied between OCV for hydraulic variable valve timing system terminals A and B.

Courtesy of MAZDA MOTORS CORP.

If the engine idles roughly or stalls, verify the condition of the timing chain assembly (valve timing). If the engine does not idle roughly or stall, perform the following inspections.

1. OCV for hydraulic variable valve timing system coil resistance inspection and spool valve operation inspection (See COIL RESISTANCE INSPECTION .) (See SPOOL VALVE OPERATION INSPECTION .)
2. Inspect the following wiring harnesses and connectors between the OCV for hydraulic variable valve timing system and PCM for an open and short circuit.
   • Between OCV for hydraulic variable valve timing system terminal A and PCM terminal 1CO
   • Between OCV for hydraulic variable valve timing system terminal B and F12 15A fuse, and F12 15A fuse and main relay terminal C
3. Inspect the oil passage for clogging and leakage.

   Oil passage 

   • Between engine oil solenoid valve and OCV for hydraulic variable valve timing system
   • Between OCV for hydraulic variable valve timing system and camshaft
   • Oil passage inside camshaft
4. If the inspection items are normal, replace the hydraulic variable valve timing actuator. (See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION .)