Fault code P0780 is called “Shift Malfunction” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P0780
This diagnostic trouble code (DTC) is a generic transmission code. Error P0780 is considered a general code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.
Stored code P0780 means that the powertrain control module (PCM) has detected a problem with the automatic transmission shifting. It can be caused by either a mechanical or electronic fault, but applies only to vehicles with automatic transmissions.
Automatic transmissions are controlled by the PCM or a separate transmission control module (TCM). Inputs from multiple engine and transmission sensors are used by the controller to calculate a shift strategy.
The controller then activates electronic solenoid valves, allowing high-pressure fluid to flow into the appropriate hydraulic circuit. That ensures the transmission shifts up or down as needed.
The transmission controller is programmed to compare signals from the input and output speed sensors to determine if the transmission is shifting efficiently. If the PCM detects that the transmission is not shifting properly, code P0780 is stored in memory.
After the code is stored, the malfunction indicator lamp (MIL) may illuminate. On some models, it takes several cycles of driving with failure for the MIL to illuminate.
Symptoms of vehicle malfunctions
The main signal that an error P0780 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be memorized as a fault).
- Other related fault codes may also be present.
- The transmission is slipping when shifting.
- Transmission is stuck in gear.
- Delayed gear engagement.
- Hard gear shifting.
- Transmission overheating.
- Increased fuel consumption.
- Howling sound from the transmission pump.
- Vehicle goes to the emergency mode.
The severity of fault code P0780 is high, it is recommended to correct it as soon as possible. If ignored, internal transmission damage may occur, which may result in costly repairs.
Factors that can cause this error code
The error code P0780 can mean that one or more of the following problems have occurred:
- The pressure control solenoid valve is defective.
- Faulty shift solenoid.
- Defective input or output speed sensors.
- Contaminated fluid or clogged transmission filter.
- Low transmission fluid level.
- Clogged transmission fluid passages.
- Faulty transmission pump or transmission valve housing.
- Other mechanical problems inside the transmission.
- A wiring problem or damaged connector.
- In rare cases, PCM malfunction.
How to fix or reset OBD-2 code P0780
Some suggested steps for troubleshooting and fix the error code P0780:
- Change the ATF fluid and filters, if necessary.
- Fill the transmission fluid to the required level.
- Flush the system to clean the internal passages of the transmission.
- Test and replace the defective pressure control solenoid valve and shift solenoid if necessary.
- Repair or replace the defective transmission pump as well as the transmission valve housing.
- Check the input or output speed sensors.
- Check the connectors as well as the associated wiring.
- Flash or replace the PCM if necessary.
Diagnose and repair of problems
Before you begin the process of troubleshooting P0780, you should research the Technical Service Bulletins (TSBs) for your particular vehicle. In some cases, this can save a lot of time by pointing you in the right direction.
Next, you should check the fluid level and determine its condition for contamination. Before changing the fluid, you should check the vehicle’s records to see when the filter and fluid were last changed.
This code may be caused by an electronic or mechanical malfunction, so you should check the transmission, cooler and coolant lines for leaks. If there is not enough fluid in the transmission, it will cause slippage, improper shifting, or delayed gear engagement.
A detailed visual inspection should then be performed to check the wiring for obvious defects. Check the connectors and wiring to the transmission pressure control solenoid valve, transmission pump and PCM. Depending on the configuration, the transmission pump may be electrically or mechanically driven.
Normal readings for wiring and connections should be 0 ohms of resistance. Wiring continuity checks should always be performed with power disconnected from the circuit. To avoid short-circuiting and creating additional damage.
Resistance or lack of continuity indicates faulty wiring that is open or shorted. In this case, repair or replacement will be required to correct error P0780.
On which vehicles does this problem occur most frequently
Fault code P0780 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Acura (MDX)
- Audi
- Citroen
- Ford
- Honda (Accord, CR-V, Civic, Jazz, Odyssey, Pilot, Stream)
- Infiniti
- Mazda (3, CX-5, CX-9)
- Mercedes-Benz
- Nissan (Maxima)
- Opel (Astra, Vectra)
- Peugeot
- Saab (9-5)
- Volkswagen
- Volvo
- LADA (Granta, Vesta)
Fault code P0780 can sometimes be found with other errors. The most common are the following: P0335, P0700, P0722, P0730, P0740, P0840, P0909, P0919, P1739, P1750, P2646.
