P0077 - INTAKE VALVE CONTROL SOLENOID, BANK 1 - CIRCUIT HIGH

To achieve the appropriate operation in the internal combustion engine, valves need to be opened or closed at different cycle points as needed. For example, the valves must be open to allow air and fuel to enter the cylinder during intake. On compression and power, the intake and exhaust valves should be closed. Besides, the valves open to allow exhaust through the intake manifold during exhaust.

To achieve the best results, modern engines are equipped with Variable Valve Timing (VVT). This system achieves on-demand performance and fuel economy. Depending on the engine speed and load, the Engine Control Module (ECM) adjusts the valve. To do this, it modulates a solenoid valve in the VVT which controls the engine oil pressure.

If the ECM detects an out-of-spec voltage in the VVT solenoid valve circuit, the DTC P0077 OBDII will be set.

• Check Engine light ON.
• Decreases fuel efficiency.
• Acceleration deficiencies.

Reasons for setting the P0077 OBD2 fault code:

• The wiring harness or VVT system circuit connectors may have been damaged.
• The Intake Valve Control Solenoid circuit may be shorted.
• The solenoid controlling the intake valve may be faulty.

For the correct diagnosis and subsequent correction of the P0077 OBDII diagnostic code, take into account this:

• Check the intake valve solenoid connector on the VVT system. Check for corroded or bent pins. Repair or replace.
• While the engine is running, verify that the solenoid has voltage from the battery. If voltage is not present, it is due to an open circuit between the ECM and valve. Replace any bad wires.
• If voltage is right, check grounding. Repair if necessary.
• Change the intake valve control solenoid.