Previous No. 1 vacuum transmitting hose routing. The hose is clamped to the cylinder head cover at three points.
Photo courtesy of Mitchell 1
Example of the new hose routing. 1) No. 1 vacuum transmitting hose clamped to the cylinder head cover at one point; 2) The hose does not clamp to this point on the cylinder head cover; 3) Additional clamp point where the vacuum hose is secured to an adjacent hose with a hose clamp.
This bulletin applies to 2016-2017 Lexus GS200T/IS200T/RC200T, 2018-2019 GS300/IS300/NX300/RC300, and 2015-2017 NX200T vehicles.
Some vehicles equipped with the 8AR engine may exhibit a rocking (forward and back) sensation that can be felt between 30 and 70 miles per hour under steady/high throttle input and/or a buzzing noise from the engine compartment. The buzzing noise may be present from the vacuum regulating valve (VRV).
Unplug the VRV and observe if the noise is no longer present.
An erratically fluctuating turbo boost gauge-equipped (only on F-Sport vehicles) may be observed during the surge condition.
Replace the vacuum regulating valve and replace the No. 1 vacuum transmitting hose with the new No. 1 vacuum transmitting hose, noting the new routing.
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