In this video, we’re going to take a look at the function of Toyota’s VVT-i and VVT-iE variable valve timing system on the 2.5 liter A25A-FKS engine. Today’s subject vehicle is a 2019 Camry.
VVT-iE is used on the intake camshaft and controls cam timing using an electric motor and an electric driving unit or EDU in one assembly. Cam timing can be advanced or retarded.
VVT-i is used on the exhaust camshaft and is a conventional electrical / hydraulic adjustment system. Cam timing can be advanced or retarded.
Both systems will set fault codes we are accustomed to seeing, like a P0016 and a P0017.
A fault for over-advanced or over-retarded timing will set when the ECM detects a difference between the target and actual cam timing. Most times this will be when a large adjustment is made but the actual movement is small.
A fault for cam / crank position correlation can set when the ECM checks the learning value at idle. Learning value is a calibration based on cam and crank position. At idle, intake valve timing is set to the fully retarded position and exhaust camshaft timing is set to the most advanced angle. If the learned value at idle is out of spec, a fault code is set.
Specific faults for the VVT-iE can be set. For example actuator circuit faults. The ECM will set a fault code when the target duty cycle does not match the actual duty cycle. The ECM monitors circuit current to determine the actual duty cycle. If using scan data, you want to see nothing more than a 4 degree difference.
The quickest and easiest way to check camshaft timing is using iSCAN diagnostic software. In the Engine submenu within the drive menu.
Our advanced testing using a scope was connected to:
The VVT-iE EDU assembly has a six wire connector
Terminal 1 is VTP Motor Operation Request. Channel 1 on our scope
Terminal 2 is VB1 battery positive supply from the VVT relay. Channel 2 on our scope, measuring current
Terminal 3 is chassis ground. Not monitored on our scope. We tested this independently with a voltage drop test.
Terminal 4 is VTM Diagnostic Signal Output. Channel 3 on our scope
Terminal 5 is VTD Motor Rotation Signal Output Channel 4 on our scope
Terminal 6 is VTS Motor Rotation Signal Output Channel 5 on our scope
iSCAN sf: www.iscantech.com/iscan-sf/
iSCAN: www.iscantech.com/
Need help with a diagnostic issue. contact iSCAN Support On Demand SOD: www.iscantech.com/sod/