P0977: Solenoid B Control Circuit High

P0977 – OBD-II Trouble Code Technical Description

Solenoid B control circuit high

What does the fault code mean P0977?

Trouble code P0977 refers to the Pressure Control Solenoid “B” Control Circuit High. This code indicates a problem with the electrical circuit that controls solenoid B, which regulates the pressure in the torque converter (also known as the transmission torque converter or torque converter).

Possible reasons

Possible causes of the P0977 trouble code may include:

1. Solenoid B fault: Problems with the solenoid valve itself, such as a short circuit or open circuit.
2. Damaged wires or connectors: Problems with wires, connections or connectors in an electrical circuit, including corrosion.
3. Problems with the electrical transmission system: For example, problems with the transmission controller or other control system components.
4. Problems with sensors or position sensors: Problems with sensors responsible for monitoring pressure or position inside the transmission torque converter.

To accurately determine and resolve the cause of the P0977 trouble code, it is recommended that you consult the service manual for your specific vehicle make and model. Diagnosis and repair should be performed by a qualified technician or auto mechanic equipped with the necessary tools and equipment.

What are the symptoms of a fault code? P0977?

Trouble code P0977 indicates a problem in the transmission torque converter solenoid B control circuit. Symptoms associated with this code may vary depending on the specific problem, but typically they may include the following:

1. Gearshift problems: Gear shifting may become harsher, jerkier, or inappropriate. This may manifest itself as delayed shifting, shifting jerks, or uneven transmission operation.
2. Unusual noises: There may be unusual noises such as knocking, squeaking, or humming noises associated with the transmission. This may be due to incorrect pressure in the torque converter.
3. Increased fuel consumption: Unregulated transmission pressure can result in increased fuel consumption because the transmission may operate less efficiently.
4. Check Engine Light Illuminates: When the transmission control system detects a problem, it may activate the Check Engine light on the dashboard.

If you experience these symptoms, especially when your Check Engine Light is activated, it is recommended that you contact a qualified auto mechanic to diagnose and repair the problem.

How to diagnose a fault code P0977?

To diagnose the P0977 trouble code and identify the correct source of the problem, you can follow these steps:

1. Scanning error codes: Use a diagnostic scan tool to read error codes in the electronic engine and transmission control system. The P0977 code will indicate a specific problem with the B solenoid control in the transmission.
2. Checking wiring and connectors: Visually check the wiring and connectors associated with the B solenoid. Look for damage, corrosion, or breaks. Disconnect and check the connectors for signs of poor contact.
3. Resistance measurement: Using a multimeter, measure the resistance in the B solenoid circuit. The normal resistance may be listed in the service manual for your specific vehicle make and model.
4. Check Solenoid B: Check solenoid B itself for corrosion, breaks or other mechanical damage. If necessary, replace the solenoid.
5. Checking transmission pressure: Use a diagnostic scan tool to monitor transmission pressure while the vehicle is running. Low or high pressure may indicate a problem with the solenoid control.
6. Checking sensors and sensors: Check the operation of transmission-related sensors such as position and pressure sensors.
7. Checking the electrical transmission system: Check transmission control system components, such as the transmission controller, for damage or malfunction.
8. Professional diagnostics: If you cannot identify and fix the problem yourself, it is recommended that you contact a professional auto mechanic or service center. They may use more advanced diagnostic methods, such as testing using special equipment.

Don't forget that diagnosing and repairing transmissions requires certain skills and experience, so if you do not have the relevant experience, it is better to turn to professionals.

Diagnostic errors

When diagnosing trouble code P0977 (Pressure Control Solenoid “B” Control Circuit High), some common errors may occur. It is important to be careful and avoid the following mistakes:

1. Skip visual inspection of wires and connectors: Some technicians may neglect to visually inspect wires and connectors, which can result in problems such as breaks, corrosion, or loose connections being missed.
2. Ignoring other error codes: Sometimes transmission problems can trigger multiple error codes. It is important to check all codes to ensure you don't miss any related issues.
3. Replacement of components without additional testing: Replacing the B solenoid or other components without thorough diagnostics can be ineffective and costly. All necessary tests must be carried out to ensure that a particular component is faulty.
4. Faulty interpretation of sensor data: Misinterpretation of data from sensors such as pressure or position sensors can lead to misdiagnosis. Check the operation of the sensors before deciding to replace components.
5. Unaccounted environmental factors: Some problems, such as electromagnetic interference or humidity, can affect the operation of electrical components. They should also be taken into account when diagnosing.
6. Insufficient transmission pressure check: Measuring transmission pressure can be a key diagnostic step. Don't skip this test to rule out blood pressure problems.
7. Insufficient recourse to professionals: If diagnosis becomes difficult, it is important to contact an experienced technician or service center for professional assistance.

Successful diagnosis requires a systematic and careful approach, and skipping these steps can lead to incorrect conclusions.

How serious is the fault code? P0977?

Trouble code P0977 indicates problems with solenoid B control in the transmission torque converter. The severity of this problem can vary depending on several factors:

1. Impact on transmission operation: Problems with the solenoid control can affect transmission performance, resulting in delayed shifting, jerking, erratic operation, and other symptoms. This can significantly impair handling and driving comfort.
2. Fuel consumption: Incorrect transmission operation can affect fuel consumption. For example, if the transmission does not shift on time or operates inefficiently, fuel economy can be affected.
3. Possible damage: If the problem is not addressed in a timely manner, it can cause further damage to the transmission or other vehicle components.
4. Potential Hazards: In some cases, if transmission problems are ignored, it can cause an accident or other dangerous situations on the road.

Therefore, the P0977 trouble code should be taken seriously and it is recommended that you begin diagnosing and repairing the problem as soon as possible. If you notice symptoms associated with this code or are concerned about the Check Engine Light on your dashboard, it is recommended that you take it to a qualified mechanic for diagnosis and repair.

What repair will help eliminate the code? P0977?

Troubleshooting the P0977 trouble code may vary depending on the specific cause of the code. Here are some possible repair steps:

1. Replacing Solenoid B: If diagnostics indicate that solenoid B is faulty, it may need to be replaced. Solenoids can be relatively affordable to replace, but certain procedures and safety guidelines must be followed.
2. Repair or replacement of wiring and connectors: If the problem is due to damaged wiring, corrosion, or breaks in the electrical circuit, repair or replacement of damaged components will be required.
3. Checking and replacing sensors: Checking transmission-related sensors may also be necessary. If the pressure or position sensors are not functioning properly, they may need to be replaced.
4. Checking and replacing the transmission controller: In some cases, problems may be due to a faulty transmission controller. After diagnosis, it may require repair or replacement.
5. Checking transmission pressure: Measuring the transmission pressure can help identify pressure problems that may be related to solenoid B control.

It is important to note that the repair should be carried out by a qualified auto mechanic or transmission specialist as it requires specific skills and equipment. Before carrying out repairs, it is recommended to perform a thorough diagnosis to accurately determine the cause and eliminate the problem.

What is P0977 Engine Code [Quick Guide]

P0977 – Brand-specific information

1. Ford, Lincoln, Mercury:
   • P0977: Shift Solenoid “B” Control Circuit High
2. Chevrolet, GMC, Cadillac, Buick:
   • P0977: Shift Solenoid “B” Control Circuit High
3. Toyota, Lexus:
   • P0977: Shift Solenoid “B” Control Circuit High
4. Honda, Acura:
   • P0977: Shift Solenoid “B” Control Circuit High
5. Nissan, Infiniti:
   • P0977: Shift Solenoid “B” Control Circuit High
6. Volkswagen, Audi, Porsche:
   • P0977: Shift Solenoid “B” Control Circuit High
7. BMW, Mini:
   • P0977: Shift Solenoid “B” Control Circuit High
8. Mercedes Benz:
   • P0977: Shift Solenoid “B” Control Circuit High
9. Subaru:
   • P0977: Shift Solenoid “B” Control Circuit High
10. Hyundai, Kia:
    • P0977: Shift Solenoid “B” Control Circuit High

Please note that this is a general interpretation and each manufacturer may have their own unique code descriptions. For more accurate vehicle-specific information, it is recommended that you refer to the official service manuals available from the manufacturer or contact your dealer.