P0664
Intake Manifold Tuning Valve Control Circuit Low (Bank 2)
Powertrain Fuel and Air Metering Intake Valve Control 🟡 Moderate — Fix within a week
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What This Actually Means
In plain language — no jargon

The engine computer detected a weak electrical signal from the intake manifold tuning valve on bank 2, similar to a dimmed light bulb that should be bright. This valve controls airflow to optimize engine performance, and a low signal means the computer can't properly command it.

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Symptoms You May Notice
3 known symptoms for this code
Check Engine Light illuminated
Rough idle or hesitation during acceleration
Reduced fuel economy and engine performance
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors the control circuit voltage to the intake manifold tuning valve solenoid on bank 2. It expects sufficient voltage and current flow when commanding the valve open or closed. A low voltage condition indicates a wiring fault, poor connection, or internal solenoid failure.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Control Circuit Voltage 10.5–14.5 V during command Below 4 V or no signal detected
Solenoid Resistance 5–15 ohms Open circuit or excessive resistance
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Wiring harness and connectors
Inspect and clean the solenoid connector on bank 2; reseat loose connections and repair corroded pins.
2
Intake manifold tuning valve solenoid
Test resistance with a multimeter; if open or shorted, replace the solenoid assembly.
3
Engine control module wiring
Check for damaged wires between the ECM and solenoid; repair or replace compromised sections.