DTC P16B8-71: Multi Flow Control Valve Actuator Stuck [10/2022 - ]: Description
WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
In the water control valve, the ball valve installed at the opening is rotated by the DC motor. This changes the coolant flow distributed to each port of the radiator, heater and devices (A/T oil cooler, etc.) or stops the coolant flow partially or completely, in order to improve fuel economy and air conditioning performance.
This is a highly functional coolant control valve that is used instead of a conventional thermostat.
- Coolant flow control: Variable control from water stop to maximum flow is performed for fast warm-up and knocking prevention
- Coolant passage control:
- Fully closed for fast engine warm-up
- Radiator port closes slightly in low and medium load ranges (high coolant temperature control)
- Radiator port opens slightly in the knocking range at high loads (low coolant temperature control)
- Heater port opens when heater is requested
- Heater port closes when air conditioning max cool is requested
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | DTC Output from | Priority | Note |
|---|---|---|---|---|---|---|---|
| P16B8-71 | Multi Flow Control Valve Actuator Stuck | Operation speed of ball valve of water control valve is below 5°/65 ms (2 trip detection logic). | Water control valve | Comes on | Engine | B |
|