Camry 2.4L (PZEV)
The intake manifold runner valve assembly has been adopted in the intake manifold. See Fig 1. This valve is actuated by the intake manifold runner valve control, which aims at improving the combustion efficiency while a cold engine is idling.
When the engine is cold condition and idling, this control closes the intake manifold runner valve (with an opening at the top) that is provided in the intake manifold. See Fig 2. This creates a strong tumble airflow in the intake air that passes through the opening, which promotes the mixture of the air and fuel and improves combustion efficiency.
The intake manifold runner valve assembly consists primarily of an intake manifold runner valve, valve body, and an intake manifold runner valve motor assembly. Each cylinder contains 1 intake manifold runner valve, which is mounted on the valve shaft axis. The intake manifold runner valve motor assembly consists primarily of a DC motor that rotates the runner valve (valve shaft), a position sensor (Hall IC) that detects the rotating position, and a gear portion that transmits the rotation of the DC motor to the valve shaft. See Fig 3.
The valve position sensor, which is a non-contact type that uses a Hall IC and a magnet, is mounted on the valve shaft axis. The valve position sensor detects the opening position of the runner valve. This sensor gives the ECM feedback on the opening position of the runner valve, which is used for SFI control, as well as for detecting the failure of the runner valve, such as if the runner valve is stuck.
The ECM fully closes the intake manifold runner valve during engine idling when the engine coolant temperature is between 14°F (-10°C) and 140°F (60°C) and the intake air temperature is more than 14°F (-10°C). See Fig 4. Other than this condition, the ECM fully opens the intake manifold runner valve. When the engine is stopped, the intake manifold runner valve is kept in a half-open condition to ensure the engine startability.
The ECM detects a "low sensor output failure" (DTC P2016) when the output voltage of the valve position sensor is 0.2 volt or less, and a "high sensor output failure" (DTC P2017) when the output voltage is 4.8 volts or more. See DTC P2014, P2016 & 2017: INTAKE MANIFOLD RUNNER POSITION SENSOR CIRCUIT under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - CAMRY 4-CYLINDER (PZEV) article.