Open circuit or short to earth in the tuning valve control wiring on Bank 2; Corroded, loose or damaged connector at the tuning valve or control unit; Faulty intake manifold tuning valve solenoid or actuator (internal short); Blown fuse or missing power supply to the valve circuit; Vacuum-operated actuator or linkage fault causing circuit or feedback issues (design dependent); Fault within the engine control unit driver circuit.

P0664

Intake Manifold Tuning Valve Control Circuit Low Bank 2.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
64: FaultThe specific fault in that area

What it means

P0664 means the engine control unit has detected a low voltage or low signal state in the control circuit for the Bank 2 intake manifold tuning valve. The control unit monitors the circuit when it commands the valve on or off, and sets the code when the voltage does not match the commanded state. The valve alters the intake runner length or airflow path to improve torque and power across the rev range, and its layout depends on the engine.

Symptoms

Malfunction indicator lamp on
Loss of power or flat spot at certain engine speeds
Reduced mid-range torque or top-end power
Rough or uneven idle
Poorer fuel economy
Engine may default to a fixed manifold setting (limp-style strategy)

Possible causes

Open circuit or short to earth in the tuning valve control wiring on Bank 2likely
Corroded, loose or damaged connector at the tuning valve or control unitlikely
Faulty intake manifold tuning valve solenoid or actuator (internal short)likely
Blown fuse or missing power supply to the valve circuitpossible
Vacuum-operated actuator or linkage fault causing circuit or feedback issues (design dependent)possible
Fault within the engine control unit driver circuitrare

How to diagnose

Read the stored and pending codes and note the freeze frame data, including engine speed, load and temperature when the fault set
Check for other related codes, especially for Bank 1 tuning valve or supply voltage faults, and deal with those first
Visually inspect the Bank 2 tuning valve, its connector and the wiring for chafing, heat damage, corrosion or water ingress
Check the relevant fuse and the power supply and earth at the valve connector against the manufacturer wiring diagram
Measure the valve coil resistance and compare with the specification for that engine
Command the valve on and off with a suitable scan tool and listen or feel for operation, and watch the control voltage change
Test the control wire for continuity and for short to earth between the connector and the control unit
Check any vacuum supply, hoses and the actuator linkage for leaks or sticking, if the engine uses them

How to fix

Repair or replace damaged wiring and ensure the connections are secure and sealed
Clean or replace corroded or damaged connectors and terminals
Replace the Bank 2 intake manifold tuning valve or actuator if it fails electrical or operation tests
Replace the blown fuse after finding and correcting the cause of the overload
Repair or replace leaking vacuum lines or a sticking linkage where fitted
Following confirmed circuit tests, repair or replace the control unit only as a last resort, then clear the code and road test to confirm

Can I keep driving?

Low severity

The car can usually be driven carefully while you book a repair, as the fault mainly affects performance and economy. Have it checked soon, particularly if power loss or a rough idle becomes noticeable.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.