P0077 GMC Intake Valve Control Solenoid Circuit High Bank 1

Possible causes

– Faulty Intake Valve Control Solenoid Bank 1
– Intake Valve Control Solenoid Circuit Bank 1 harness is open or shorted
– Intake Valve Control Solenoid Circuit Bank 1 circuit poor electrical connection

What about the obd code?

An improper voltage is sent to the Engine Control Module (ECM) through intake valve timing control solenoid valve.

Symptoms

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

P0077 GMC Description

Intake valve timing control solenoid valve is activated by ON/OFF pulse duty (ratio) signals from the Engine Control Module (ECM).

The intake valve timing control solenoid valve changes the oil amount and direction of flow through intake valve timing control unit or stops oil flow.

The longer pulse width advances valve angle. The shorter pulse width retards valve angle. When ON and OFF pulse widths become equal, the solenoid valve stops oil pressure flow to fix the intake valve angle at the control position.