MX-5 Miata L4-2.0L (2008)
Variable Valve Timing Actuator: Component Tests and General Diagnostics
Variable Valve Timing Control System Operation Inspection
Variable Valve Timing Control System Operation Inspection
If simulation function of WDS or equivalent is used:
1. Warm up the engine to normal operating temperature.
2. Connect the WDS or equivalent to DLC-2.
3. Start the engine and run it at idle.
4. Select VT DUTY1 PID.
5. Increase the oil control valve (OCV) duty value and verify that the engine idles roughly or stalls.
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If as specified, inspect the timing belt component (valve timing deviation).
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If not as specified, go to the next step.
6. Remove the oil control valve (OCV) with connector is connected.
7. Turn the ignition switch to the ON position.
8. Select VT DUTY1 PID.
9. Increase the oil control valve (OCV) duty value and verify that the spool valve operates in the advance direction.
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If as specified, inspect the following hydraulic passage for clogging and/or leakage.
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Oil pressure switch-oil control valve (OCV)
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Oil control valve (OCV)-camshaft
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Camshaft internal passage
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If not as specified, inspect the following:
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Oil control valve (OCV) operation
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Harness and connectors for open or short (Oil control valve (OCV)-PCM terminal 2E)
10. If they are okay, replace the intake camshaft pulley (with a built-in variable valve timing actuator).
If simulation function of WDS or equivalent is not used:
1. Start the engine and run it at idle.
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If idling cannot be continued, go to Step 2.
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If idling can be continued, go to Step 7.
2. Remove the oil control valve (OCV) and verify that the spool valve is at maximum retard position.
3. Connect the oil control valve (OCV).
4. Turn the ignition switch to the ON position.
5. Verify that the spool valve is at maximum retard position.
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If the spool valve is stuck in the advance direction, inspect for the following:
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Short circuit in wiring harnesses or connectors between the oil control valve (OCV) and the PCM.
6. Inspect the variable valve timing actuator.
7. Disconnect oil control valve (OCV) connector.
8. Warm up the engine and idle it.
9. Apply battery voltage to the oil control valve (OCV) and verify that the engine idles roughly or stalls.
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If the engine idles roughly or stalls, inspect the timing belt component (valve timing deviation).
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If the engine does not idle roughly or stalls, go to the next step.
10. Remove the oil control valve (OCV) and perform spool valve operation inspection.
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If not as specified, inspect the following:
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Oil control valve (OCV)
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Harnesses and connectors between oil control valve (OCV) and PCM open or short.
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If as specified, inspect the following hydraulic passages for clogging or leakage or both:
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Oil pressure switch-oil control valve (OCV)
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Oil control valve (OCV)-camshaft
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Camshaft internal passage
11. If they are normal, replace the camshaft pulley (with built-in variable valve timing actuator).
Evaporative Emission (EVAP) System Leak Inspection
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To verify that the problem has been fixed properly after repairs, the run drive cycle or EVAP system leak inspection must be performed.
EVAP system leak inspection using WDS or equivalent
