P0660: Intake Manifold Tuning Valve Control Circuit/Open Bank 1

What does P0660 mean?

The intake manifold tuning valve switches the manifold length or plenum connection with engine speed (more torque low, more power high); it is not the runner or swirl flap (IMRC, P2004 ff). P0660 means the control circuit of the bank 1 (or only) valve is open. GM evaluates the line voltage with the driver off: too low means the supply through the coil is missing (200 kΩ or more). GM's engines with this valve (low-side driver) check with ignition voltage of at least 11 V and the engine above 400 rpm and set the code after 40 of 50 samples (about 0.6 s), with the check engine light after two trips. Ford uses P0660 (older: P1549) as the electrical check of its actuator, which has no position feedback and stays closed and unpowered below about 2600 rpm – without the check engine light (5 s). The valve then stays in its rest position and power at high revs suffers.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light (GM after two trips; Ford without)
• Less power in the upper or middle rev range
• Actuator does not click at ignition on or when switching

Common causes

• High Actuator connector loose, corroded or spread
• High Actuator coil or motor open internally
• Medium Broken or chafed wire (control or supply)
• Low Supply (fuse, main relay) to the actuator missing
• Low Output driver in the engine module faulty

Likelihood is a general estimate across vehicles; your make and model may differ.