P0780 Gear Shift Malfunction

P0780 – OBD-II Trouble Code Technical Description

Shift fault

What does the fault code mean P0780?

In my opinion, the P0780 code is related to a problem in the automatic transmission, and it can occur due to either mechanical or electronic faults. This code only applies to vehicles with automatic transmission.

Automatic transmissions in OBD-II equipped vehicles are controlled by a powertrain control module (PCM) or a standalone transmission control module (TCM). They receive information from engine and transmission sensors to determine gear shift strategies. By activating electronic solenoid valves, they control the flow of high-pressure fluid in the transmission hydraulic circuits, allowing gears to be shifted up or down as needed. To create the necessary hydraulic pressure, a powerful pump driven by an engine is used.

The transmission controller also regulates pressure using an electronic pressure regulator based on changes in engine speed and load. It uses a pressure sensor and a transmission temperature sensor to monitor pressure and adjust shifts. If the controller detects ineffective transmission shifting, it stores a P0780 code and may activate the Malfunction Indicator Light (MIL). Sometimes this code does not work right away and may require several trips to activate.

There can be a variety of reasons for the P0780 code to turn on, including mechanical problems such as a control valve that is tripping or a solenoid valve that is not operating properly, causing the transmission to shift incorrectly.

Possible reasons

Possible causes of a P0780 code include:

1. Short circuit or open circuit in the wires that control the transmission.
2. Low transmission fluid level.
3. Dirty transmission fluid.
4. Faulty shift solenoid valve.
5. Defective input or output speed sensors.
6. Problems with the electronic pressure regulator.
7. Transmission pump malfunction.
8. Mechanical damage, including torque converter failure, clutch problems, or worn/damaged internal transmission components.
9. Faulty PCM or error in PCM programming.

“Shift solenoid valve harness is open or shorted” means that the wires connecting the shift solenoid valve may be open or shorted, which can cause problems with transmission signals and control.

What are the symptoms of a fault code? P0780?

A P0780 code related to shifting should be considered critical. Even a small fault can become a serious problem if not corrected in time. Symptoms of P0780 may include:

1. Unstable gear shift pattern.
2. Delay when switching on the gear.
3. Sharp gear shifting, especially in emergency mode.
4. Transmission slippage.
5. Whistling or howling noise from the transmission pump.

These symptoms require immediate attention to avoid serious damage to the transmission and keep your vehicle running safely.

How to diagnose a fault code P0780?

When the P0780 shift related code appears, perform the following diagnostic steps:

1. Check the level and condition of the transmission fluid. Dirty or burnt fluid may indicate internal problems.
2. Visually inspect the wires and connectors in the transmission control harness for damage, corrosion, or disconnections.
3. Clear stored codes and check if the P0780 code recurs after a test drive.
4. Use the transmission pressure gauge to check the pump pressure, especially if the transmission fluid level has been low.
5. If symptoms indicate a faulty shift solenoid, consider replacing all solenoids at once if recommended by the manufacturer.
6. In the event of an electrical problem, consult the vehicle's service manual and perform the recommended wiring and solenoid checks.

It is important to note that the P0780 code can have a variety of causes and a thorough diagnosis must be performed to determine and repair the source of the problem in the transmission.

Diagnostic errors

When diagnosing the P0780 trouble code and shifting problems, mechanics may make the following mistakes:

1. Leaking Transmission Fluid Levels and Conditions: Insufficient or contaminated fluid levels can be the root cause of transmission problems. A mechanic who does not check or change the transmission fluid may miss this important aspect of diagnosis.
2. Faulty Sensors: If a mechanic does not check the condition of the input and output speed sensors or other sensors that may affect proper transmission shifting, a misdiagnosis may result.
3. Skipping Inspection of Electrical Connections: Improper wire connections, corroded or corroded contacts can cause problems with solenoids and other electronic components in the transmission. A mechanic should check the condition of all electrical connections.
4. Not knowing specific manufacturer recommendations: Different vehicles may have different problems and solutions for the P0780 code. Incorrect understanding or omission of recommendations provided by the manufacturer may lead to incorrect diagnosis and repair.
5. Insufficient Equipment and Tools: To accurately diagnose P0780 and work on the transmission, special tools are required, such as a diagnostic scanner, transmission pressure gauge, etc. A mechanic who does not have the necessary equipment may encounter limitations in diagnosis.
6. Skipping Multiple Inspections: In some cases, the P0780 code may not immediately return, and a mechanic without performing multiple inspections and test drives may miss the problem.
7. Lack of Transmission Expertise: Transmission diagnostics require experience and knowledge in the field. Ignorance of the features and functionality of the transmission can lead to incorrect conclusions.

To avoid these mistakes, it is important to contact a qualified mechanic or service center with experience in diagnosing and repairing automatic transmissions.

How serious is the fault code? P0780?

Trouble code P0780, related to automatic transmission shifting problems, should be considered serious. The occurrence of this code indicates possible problems with the transmission, which can lead to serious damage or failure in the transmission.

Symptoms associated with P0780 may include shift instability, harsh shifts, transmission slippage, and other abnormalities. If this code is not corrected and ignored, it can lead to further transmission degradation, increased component wear, and ultimately costly transmission repairs or replacement.

Therefore, if your P0780 code is illuminated or you notice symptoms that indicate shifting problems, it is recommended that you contact a qualified mechanic or service center for diagnosis and repair as soon as possible to prevent further deterioration and ensure the vehicle operates reliably and safely.

What repair will help eliminate the code? P0780?

The following repairs may be required to resolve DTC P0780 and associated automatic transmission shifting problems:

1. Checking the Transmission Fluid Level and Condition: The first step is to ensure that the transmission fluid level is correct and is in good condition. Dirty or overheated fluid can cause shifting problems.
2. Transmission Fluid and Filter Replacement: If the fluid is old and dirty, it is recommended to replace the transmission fluid and filter.
3. Diagnosing Shift Solenoids: Faulty solenoids can cause shifting problems. Check and, if necessary, replace faulty solenoids.
4. Checking Input and Output Speed ​​Sensors: Input and output speed sensors play an important role in gear shifting. Check their functionality and replace if necessary.
5. Inspecting and Repairing Wiring and Connectors: Wiring and connectors associated with solenoids and sensors can cause problems. Check them for defects, corrosion and damage.
6. Diagnose and replace the torque converter: If problems continue, you may need to check the condition of the torque converter and repair or replace it.
7. Checking the Transmission Pump: The transmission pump creates the hydraulic pressure needed to shift gears. If the pump is damaged, it must be replaced.
8. Transmission Valve Body Diagnosis: Valve body faults can cause shifting problems. Assess the condition of the case and make repairs or replacements if necessary.
9. Testing and Reprogramming the Transmission Control Module (TCM): In some cases, problems may be related to the TCM. This may require reprogramming or replacing the TCM.
10. Checking Internal Transmission Components: If all of the above steps do not resolve the problem, the internal transmission components may need to be diagnosed and repaired.

Repairs may vary depending on the specific circumstances, the make and model of the vehicle, and the specific problem. It is important to contact a qualified mechanic or service center for accurate diagnosis and repair, as shifting is an important part of your vehicle's performance and improper repairs can have serious consequences.

What is P0780 Engine Code [Quick Guide]

P0780 – Brand-specific information

Trouble code P0780 can have different meanings depending on the make of the car:

1. Toyota, Lexus: P0780 – Problem in the transmission control system.
2. Ford: P0780 – Transmission Error – There is a problem with the signals coming from the TCM (Transmission Control Module).
3. Chevrolet, GMC: P0780 – The gear selector does not operate properly.
4. Honda, Acura: P0780 – Shift solenoid malfunction.
5. Nissan, Infiniti: P0780 – Transmission error – solenoid.
6. Dodge, Chrysler, Jeep: P0780 – Inconsistency between the gear selector signals and the output shaft rotation speed.
7. Hyundai, Kia: P0780 – Problem with the shift control solenoid.
8. Volkswagen, Audi: P0780 – Transmission signal problem.

Please note that exact definitions may vary depending on the specific model and year of the vehicle. It is recommended to consult an authorized service center or mechanic who works with your brand of vehicle for an accurate diagnosis and repair of the problem.