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P0661 — Intake Manifold Tuning Valve Control Circuit Low Bank 1

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

P0661 indicates a low voltage condition in the control circuit for the Intake Manifold Tuning Valve (IMTV) on Bank 1. The code is triggered when the engine control module detects that the IMTV signal is below the required threshold.

Symptoms

What causes it — most likely first

1. Faulty Intake Manifold Tuning Valve (IMTV) solenoid

The valve may be stuck in the open or closed position, or its internal wiring may be damaged, causing low voltage readings.

2. Short or broken wiring in the IMTV circuit

A broken or frayed wire can reduce the voltage seen by the ECU, triggering the low‑circuit code.

3. Corroded or poor connector contact at the IMTV harness

Oxidation or a loose connector can interrupt the circuit, leading to a low voltage signal.

4. Ground fault in the IMTV control circuit

A broken ground path will prevent the proper voltage from reaching the ECU, which may appear as a low control circuit.

5. Engine Control Module (ECM) malfunction

Although rare, a defective ECM can misread the IMTV voltage, but this is usually a last resort after hardware issues are ruled out.

How it's diagnosed

  1. Check the IMTV solenoid for proper operation and continuity.
  2. Inspect the wiring harness and connectors for damage, corrosion, or loose connections.
  3. Measure the voltage at the IMTV connector while the engine is running to confirm a low signal.
  4. Test the IMTV ground connection for continuity.
  5. If all hardware checks out, consider a diagnostic scan of the ECM for faults.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make
Related codesP0659 — Actuator Supply Voltage Circuit HighP0660 — Intake Manifold Tuning Valve Control CP0662 — Intake Manifold Tuning Valve Control CP0663 — Intake Manifold Tuning Valve Control CP0664 — Intake Manifold Tuning Valve Control CP0665 — Intake Manifold Tuning Valve Control C

Frequently asked

Is it common to replace the PCM for a P0661 code?

No, most P0661 occurrences are due to a faulty IMTV, wiring, or connector. Replacing the PCM is rarely necessary and should only be considered after all hardware has been verified.

What does the code mean if the engine runs fine?

The code can trigger even when performance is acceptable, especially if the IMTV is marginally out of spec. It still requires a hardware check to prevent future issues.

Can I ignore a P0661 code?

While it may not immediately affect driving, it can lead to improper throttle control and fuel economy loss. It is best to address the underlying cause promptly.