Open circuit in the control wire between the PCM and the tuning valve (broken wire, corroded terminal, or disconnected connector); Failed intake manifold tuning valve actuator (open coil or internal fault); Short to voltage on the control circuit, often from chafed wiring near the intake or exhaust; Poor electrical connection at the valve or PCM connector (loose pins, corrosion, water intrusion); Faulty PCM driver for the tuning valve circuit (less common); Aftermarket or damaged components in the circuit causing excessive resistance

DTC codes / P06xx · Computer and output circuits / P0665

P0665Intake Manifold Tuning Valve Control Circuit High (Bank 2)

Q: What does code P0665 mean?

Intake Manifold Tuning Valve Control Circuit High (Bank 2). P0665 means the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for the bank 2 intake manifold tuning valve, which is the valve that changes intake runner length or volume to optimize airflow at different engine speeds. The PCM commands the valve to move and monitors the circuit; a high voltage reading usually indicates an open circuit, a short to voltage, or a faulty valve actuator.

P0665 means the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for the bank 2 intake manifold tuning valve, which is the valve that changes intake runner length or volume to optimize airflow at different engine speeds. The PCM commands the valve to move and monitors the circuit; a high voltage reading usually indicates an open circuit, a short to voltage, or a faulty valve actuator.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Slight hesitation or flat spot during acceleration, especially at lower engine speeds
Reduced engine performance or fuel economy due to improper intake tuning
Rough idle or unstable engine operation in some cases
Audible clicking or buzzing from the intake manifold area if the valve is stuck
In rare cases, the engine may enter limp mode or set related codes

Common causes, most likely first

Open circuit in the control wire between the PCM and the tuning valve (broken wire, corroded terminal, or disconnected connector)
Failed intake manifold tuning valve actuator (open coil or internal fault)
Short to voltage on the control circuit, often from chafed wiring near the intake or exhaust
Poor electrical connection at the valve or PCM connector (loose pins, corrosion, water intrusion)
Faulty PCM driver for the tuning valve circuit (less common)
Aftermarket or damaged components in the circuit causing excessive resistance

How to diagnose and fix it

Use an OBD-II scanner to verify P0665 is current and check for related codes; clear the code and test-drive to see if it returns.
Visually inspect the tuning valve connector and wiring for damage, corrosion, or loose pins; repair or replace as needed.
Disconnect the valve and measure resistance across its terminals; compare to the manufacturer's specification to rule out an open coil.
With the valve disconnected, check for voltage on the control wire with the key on and the PCM commanding the valve; a constant high voltage indicates a short to voltage.
Perform a continuity test on the control wire from the PCM to the valve to check for an open circuit; repair the wire if broken.
If the wiring and valve test good, substitute a known-good valve or use a bidirectional scan tool to command the valve and observe operation.
As a last resort, check the PCM for proper ground and power, and consider PCM replacement if all other components test good.

What a high voltage reading really means

A high voltage code on a control circuit often results from an open circuit rather than a short, because the PCM pulls the circuit high when it cannot complete the path to ground through the actuator.
The intake manifold tuning valve may be vacuum-operated or electrically controlled depending on the engine design; always confirm the system type before testing.
A stuck-open or disconnected tuning valve can cause no driveability symptoms at all, leading many to replace the PCM unnecessarily when the real issue is a broken wire.
Corrosion inside the valve connector is a frequent culprit, especially on vehicles driven in humid or salty environments, and can mimic a failed valve.
Related codes such as P0660 (bank 1 control circuit) or P2004 (intake manifold runner control stuck open) may appear if the fault affects multiple tuning valves or the same bank.

Can I keep driving with P0665?

You can generally continue driving with P0665, but avoid aggressive acceleration or heavy loads until the fault is repaired, as the engine may not perform optimally and fuel economy could suffer. If the check engine light starts flashing or you notice severe power loss, stop driving and seek professional diagnosis.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.