P0077 Faulty Code (Symptoms, Causes and How to Fix)

A customer complaining about a gear/transmission problem brought his RAV4 to our mechanic workshop.

We carried out a proper diagnostics at the workshop and the diagnostic machine displayed the P0077 fault code which indicates “Intake Valve Control Solenoid Circuit High (Bank 1)” error.

The complaint of the vehicle owner is that when the driver changes the gear it causes the vehicle to jerk, jolt, or make a loud thud when changing gears, rather than it transitioning smoothly which is also referred to as harsh shifting.

Here in this article we will discuss about P0077 faulty code that your OBD Scanner detects.

Symptoms of P0077 Faulty Code

The symptoms of P0077 faulty code includes:

• Check Engine Light.
• Reduced engine power.
• Poor acceleration.
• Increased fuel consumption.
• Jerking or Harsh Shifting
• A Burnt or dark color of the transmission oil.
• Black smoke from the exhaust

Common Causes of P0077 Faulty Code

The Code P0077 on the diagnostic scanner indicates a high-voltage circuit problem with the Bank 1 Intake Valve Control Solenoid (Oil Control Valve) and the common causes are:

• A damaged or shorted solenoid harness wire which creates a short to a 12V source.
• A defective or faulty Intake Solenoid.
• Resistance and voltage spikes caused by a corroded or loose connector.
• A damaged or faulty ECU (Engine Control Unit) which sends a wrong electrical signal to the transmission solenoid.
• Insufficient/low or contaminated Automatic Transmission Fluid (ATF) preventing the solenoid to open correctly. 

Frequently Asked Questions (FAQ)

What does code P0077 mean?

P0077 code indicates an issue with your vehicle’s transmission or gearbox. The error P0077 code will be displayed on your scanner as “Intake Valve Control Solenoid Circuit High (Bank 1)” error.

What are the symptoms of Intake Valve Control Solenoid Circuit High (Bank 1)?

The symptoms of the intake valve control solenoid circuit high (Bank1) includes:

• Check Engine Light.
• Reduced engine power.
• Poor acceleration.
• Increased fuel consumption. 
• Jerking or Harsh Shifting.
• Black smoke from the exhaust.

The best way to fix P0077 code is to replace your gearbox and the ECU (Engine Control Unit) also known as brainbox. 

Another way to fix P0077 is by cleaning the solenoid or replacing the solenoid and also ensure to replace the Engine Control Unit (ECU) or brainbox.

Ensure you fill the new transmission or gear with a new transmission fluid. The reconfigure the OBD Scanner and clear fault code if persistent.

How to fix p0077 fault code

To fix P0077 fault code :

• Replace your the solenoid on your gearbox or completely replace you gearbox.
• Replace the ECU (Engine Control Unit).
• Fill the new transmission or gear with a new transmission fluid.
• Reconfigure your OBD Scanner and clear if fault code is persistent.

What is an intake valve control solenoid?

The intake valve control solenoid circuit high (Bank1) P0077 is a fault code involving a bad or short circuit intake control valve solenoid in the gearbox and a bad ECU.

To fix this issue simply replace the gearbox or replace the faulty solenoid. If replacing the faulty solenoid reset or reprogram  the transmission control module or unit (TCM/TCU). Then flush transmission fluid and replace with a new one.

Conclusion

In Conclusion if a mechanic diagnose your vehicle with a P0077 error code this indicates a problem between your transmission and Brainbox or ECU.
Simply check if your ECU is good if not simply replace a faulty ECU. Then check your gearbox or transmission to replace it with a new one or by replacing a faulty solenoid.

Note: As a professional we recommend changing both the Transmission and ECU of your vehicle to give you a better result.