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P0665 — Intake Manifold Tuning Valve Control Circuit High Bank 2

Generic OBD-II · all makesPowertrain (engine & transmission)

P0665 indicates that the Powertrain Control Module (PCM) has detected a higher-than-expected voltage condition in the control circuit for the Intake Manifold Tuning (IMT) valve on Bank 2. The IMT valve (also called Intake Manifold Runner Control) adjusts intake runner length to optimize engine performance across different RPMs. A circuit high condition typically points to a short to voltage in the wiring, a failed valve actuator, or less commonly, a PCM output driver fault.

Symptoms

What causes it — most likely first

1. Failed IMT valve actuator (most common)

The IMT valve motor or actuator internally shorts, causing the circuit to read high voltage regardless of PCM command. This is the most frequent cause and can often be confirmed by testing resistance and operation.

2. Shorted wiring or connector damage

A wire in the IMT control circuit may be chafed, melted, or pinched against a ground source or voltage source, creating an unintended short that forces the circuit high.

3. Corroded or bent connector pins

Moisture intrusion or corrosion at the IMT valve connector or PCM connector can create a high-resistance connection that falsely signals a high-voltage condition.

4. Powertrain relay or fuse failure

If the IMT circuit shares a relay or fuse with other components, an intermittent failure may cause voltage irregularities on the control line.

5. Failed PCM output driver (least likely)

The PCM output transistor that drives the IMT valve may fail, though this is relatively rare. It should only be considered after all wiring and valve faults are definitively ruled out.

How it's diagnosed

  1. Retrieve all stored codes and freeze frame data with a scan tool to confirm P0665 and identify any related codes (such as P0664 for Bank 1, or sensor-related codes).
  2. Locate the Bank 2 IMT valve (typically on the intake manifold near the throttle body) and visually inspect for physical damage, disconnected wiring, or vacuum leaks.
  3. Unplug the IMT valve connector and measure circuit voltage with a multimeter—the circuit should show near 0V with the key on engine off if the PCM driver is off.
  4. Test the IMT valve's internal resistance against factory specifications; a shorted valve will show abnormally low resistance or a direct short to ground/voltage.
  5. Perform a continuity and insulation test on the wiring harness between the PCM and IMT valve, checking for shorts to power, ground, or other circuits.
  6. If wiring and valve test normal, check PCM power and ground supplies, then consider PCM output driver failure only after exhaustive elimination of all other causes.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make
Related codesP0660 — Intake Manifold Tuning Valve Control CP0661 — Intake Manifold Tuning Valve Control CP0662 — Intake Manifold Tuning Valve Control CP0663 — Intake Manifold Tuning Valve Control CP0664 — Intake Manifold Tuning Valve Control CP0666 — Control Module Internal Temperature Se

Frequently asked

Can a bad PCM really cause P0665?

Yes, but it is an uncommon cause. The PCM output transistor for the IMT circuit can fail, though this is far less likely than a failed valve or wiring issue. Technicians often replace the PCM unnecessarily when the real fault is the IMT valve itself.

Will P0665 cause immediate drivability failure?

Not usually. The engine will typically still run, though with reduced power, poorer fuel economy, and a rough idle. The Check Engine Light will illuminate, but the vehicle is generally still operable for short distances.

Can I drive with P0665?

Short-term driving is generally safe but not recommended. Continued operation can lead to further engine performance degradation, increased fuel consumption, and potential damage to other emissions components over time.

Why am I being told to replace the PCM for P0665?

Unfortunately, some shops and parts retailers default to PCM replacement for electrical codes because it is an easy answer, even when the PCM is not at fault. P0665 is far more commonly caused by a failed IMT valve or wiring issue. Always verify all other causes before considering PCM replacement.