What causes a P0661 code?

P0661 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a P0661 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P0661 active.

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

OBD-II

P0661

Intake Manifold Tuning Valve Control Circuit Low

What it means

The Engine Control Module (ECM) detects a low voltage or ground state in the control circuit for the intake manifold tuning valve (IMTV), indicating a potential short to ground or open circuit.