Possible causes

– Faulty Intake Manifold Tuning Valve (IMTV)
– Intake Manifold Tuning Valve harness is open or shorted
– Intake Manifold Tuning Valve circuit poor electrical connection

When is the code detected?

The Engine Control Module (ECM) has detected a high signal from the Intake Manifold Tuning Valve (IMTV)

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0665 MAZDA Description

The Intake Manifold Tuning Valve (IMTV) system is monitored for failure during continuous, key ON engine OFF or key ON engine running self-test. The test fails when the signal on the monitor pin is more or less than an the expected calibrated range