P0664 indicates the Powertrain Control Module (PCM) has detected a low voltage signal on the control circuit for the Intake Manifold Tuning Valve (IMTV) on Bank 2, which is the cylinder bank not containing cylinder #1 on V-style engines. The IMTV changes the effective length of the intake runners to improve low-end torque, and a 'low' fault means the control side of the circuit is shorted toward ground, open, or being held low by a failed component. The PCM typically disables the tuning function and illuminates the check engine light when this code is set.
The valve's electric actuator or vacuum solenoid is the most common failure point; internal short circuits or coil failures pull the control circuit low and trigger the code.
The control wire to the IMTV often runs near the intake manifold and can be burned, chafed, or pinched, allowing it to short to ground and produce a low-voltage reading at the PCM.
Heat cycling near the intake manifold breaks down connector seals; moisture intrusion and terminal corrosion create resistance or intermittent shorts that the PCM interprets as a low circuit condition.
On engines that use engine vacuum to move the runner valve, a cracked vacuum line, failed check valve, or ruptured diaphragm prevents the valve from responding to PCM commands and can set the code.
Carbon buildup, a broken link, or a seized shaft can stall the actuator and hold the circuit in a low-current state, mimicking an electrical fault.
An internal driver fault in the Powertrain Control Module can pull the control circuit low, but this is uncommon and should only be considered after every other cause has been ruled out.
Yes, in most cases. The engine will typically run, but the intake manifold tuning feature will be disabled, which may reduce low-end torque and fuel economy. Have it diagnosed soon to avoid masking related issues.
Clearing the code will turn the light off temporarily, but the PCM will re-detect the fault and the light will return, usually within one or two drive cycles. The underlying cause still needs repair.
Almost never. Online posts and parts counters sometimes suggest replacing the computer, but P0664 is caused by the IMTV component, its wiring, or a connector in the vast majority of real-world cases. The PCM should only be suspected after every wiring, connector, and actuator test points to a known-good result.
No. Bank 1 is defined as the cylinder bank that contains cylinder #1; Bank 2 is the opposite bank. On inline engines there is no bank distinction, so P0664 (and any 'Bank 2' code) typically does not apply to four-cylinder engines.