Variable Valve Timing Control Block Diagram [Lf]; Variable Valve Timing Control Operation [Lf]; Cleaning Mode - Mazda 2006 MX-5 Service Highlights

VARIABLE INTAKE AIR CONTROL OPERATION [LF]
Operation conditions
• If any of the following conditions are met:
— Engine speed is approx. 4,750 rpm or more
— Engine speed is approx. 3,150 rpm or less and the throttle opening angle is the specified value or more.
(heavy load condition)
When operation conditions are not met
• The PCM energizes the variable intake air solenoid valve, closing the variable intake air shutter valve to
enhance the inertia charging effect in the engine low to middle speeds and low load ranges.
When operation conditions are met
• The PCM blocks energization the variable intake air solenoid valve, opening the variable intake air shutter valve
to enhance the inertia charging effect in the engine high speed and high-load range.
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VARIABLE VALVE TIMING CONTROL OUTLINE [LF]
• Variable valve timing control changes the intake valve timing according to engine operation conditions to
improve engine output, fuel economy, and exhaust emission performance.
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VARIABLE VALVE TIMING CONTROL BLOCK DIAGRAM [LF]

• Based on the signals from the input sensors, the PCM determines the valve timing suitable for the engine
operation conditions, drives the OCV, and switches the hydraulic passages of the variable valve timing actuator
to provide appropriate valve timing.
ECT SENSOR
CKP SENSOR
CMP SENSOR
TP SENSOR NO.1, NO.2
MAF SENSOR
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VARIABLE VALVE TIMING CONTROL OPERATION [LF]

• The PCM divides the oil control valve OCV drive range into four modes according to engine operation
conditions. The OCV drive current is determined based on the target current calculated in each mode.

Cleaning Mode

Mode execution condition
• When the following condition is met:
— Idle speed control feedback execution condition
Purpose
• Cleaning mode is to remove foreign material in the OCV hydraulic passages.
Operation
• The target current in the cleaning mode is fixed at 100 mA or 1,000 mA. A current of 100 mA and 1,000 mA
flows to the OCV alternately at certain intervals. When 100 mA current is supplied, the OCV opens the
hydraulic passage for the retard chamber and hydraulic pressure from the oil pump is introduced to the retard
chamber. When 1,000 mA current is supplied, the OCV opens the hydraulic passage for the advance chamber
and hydraulic pressure is introduced from the oil pump to the advance chamber. After repeating this operation
several times, foreign material mixed in the OCV is removed and the cleaning mode is completed.
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CONTROL SYSTEM
PCM
E5U014000000N18
E5U014000000N22
E5U014000000N23
OCV
E5U140ZT5100
E5U014000000N63