Ford P1780– Meaning, Causes, Symptoms, & Fixes

Many codes can be seen in your Ford vehicle. Each code carries its meaning and risk. Therefore, it’s crucial to have insights about them to avoid issues such as slow acceleration, reduced fuel economy, and even loss of control. For example, code p1780 in your Ford can indicate that something is wrong. Understanding what that is and whether it’s a severe issue can help you resolve it quickly, reducing maintenance costs and extreme damage to your car. You have probably received this code recently and are looking for answers to it. This article will help you understand everything about it. So, without wasting your time, let’s get on it.

What does code p1780 mean?

 Does your Ford vehicle have an automatic transmission? If yes, it’s equipped with a transmission control switch (TCS). This switch is attached to the gear selector, and its purpose is to prevent your car’s transmission from switching into overdrive. This is achieved when you push it. It is usually accompanied by the illumination of the transmission control switch lamp (TCSL). However, if there is an issue with the TCS or TCSL, the power control module (PCM) will detect it, and code p1780 will be shown.

How does the Ford p1780 code come about?

 When you ignite your Ford, the Electric Control Module (ECL) runs a self-test known as a Key On Engine Running (KOER). This tests all the components in your car, such as the TCS and TCSL. The process cycles the TSC, and if an issue is identified, code p1780 is returned.

Symptoms of Ford p1780

 Many symptoms do not usually accompany code p1780. That is why it is not usually taken seriously. However, you should check three main things when your Ford displays it. These are:

 i. Not working overdrive

As mentioned above, the TCS prevents the car’s transmission from entering an overdrive state. Therefore, if the TCS fails, the transmission will fail to either enter into overdrive or come out of overdrive. To test if the overdrive is working, allow your car to travel at a constant speed of around 80 kph and then engage the TCS. If the overdrive is working, your Ford’s engine speed will fall by more than 500 rpm while the car’s speed will be maintained.

 ii. Check engine light will come on

A check engine light typically comes on when your car has a problem. Therefore, the Ford p1780 code will usually be followed by an illuminated check engine light. But since the check engine light indicates any vehicle issue, it cannot be wholly relied upon to tell if it is associated with the Ford p1780 code.

 iii. No light in the TSC Indicator Lamp

Ford p1780 code will be accompanied by a TSC indicator lamp that will not illuminate. So, one way to know if you have code p1780 is by checking that lamp. However, this is not a sure symptom since the lamp itself could be wrong, but the transmission signals are reaching it. As such, you should check other symptoms first.

 What causes Ford p1780?

Many things can cause code p1780 in your Ford. These causes could be an issue with the transmission system or the computer. Below are the main things you should check when you encounter code p1780.

 1. Malfunctioned PCM

 The PCM is responsible for monitoring and controlling many parts of your Ford vehicle, including the engine and the transmission. For instance, when you press the TCS knob, a signal will be relayed to the PCM, resulting in no gear movement. However, if the signal does not reach the PCM or the PCM itself is faulty, code p1780 will be thrown.

The PCM can fail to function due to a software problem. If the PCM develops bugs, it will fail to detect and interpret the signals sent from the transmission. Fortunately, you can easily fix the bug issue by simply rebooting the PCM. Your Ford manual should contain instructions on how to do it.

 If, after rebooting, you still get the error code, your car’s PCM may be faulty. Things such as excessive heat and vibrations can make the PCM go bad. You can check if it’s damaged by manually inspecting it. But this may require skills you don’t have; hence you may want to consult an expert.

2. Transmission Control (TC) harness is shorted

For the TCS to function correctly, it must receive electric current from the car’s battery. This is made possible by its wires which make up a circuit. Unfortunately, water can enter into the circuit, and damage it by causing a short circuit. This will also interrupt the TCS and the PCM communication since the signals need such current to move. Remember that water is not the only thing that damages the wire harnesses. Acid vapor from the battery can also make the wires peel off and come in contact with each other.

Fortunately, a bad TC circuit can easily be identified. All you have to do is disconnect the TCS and use a test light to check if the circuit is working. If the test light fails to illuminate, the circuit is defective. You can repair a bad circuit by replacing the wire harnesses.

3. The electrical connection is loose

Sometimes there is a loose connection in the battery or the transmission control circuit. Constant expansion and contraction of the wires and the parts that hold them to the battery will cause this issue. A bad electrical connection will affect the transfer of electric current to the TCS. This will, in turn, be detected by the PCM, resulting in code p1780. Luckily, a loose wire connection will produce sparks which can easily be observed and fixed by tightening the connections.

4. Transmission Control Switch (TCS) is broken

 If the cables are in good condition, you should check if the TCS is broken. You can do so using a multimeter. When you press the multimeter, it should read around 5 ohms. If it reads less than that, the TCS is bad. Sadly, it’s not advisable to repair a damaged TSC. Therefore, try to get a new one to fix code p1780 once and for all.

 5. Bad battery

 As mentioned above, the transmission control circuit relies on electric current from the battery to function. Therefore, f it receives low or no voltage from the battery, code p1780 will be shown in your Ford Vehicle. The battery can fail to operate optimally due to many things, such as old age, overcharging, overheating, and over-usage. So, one way to fix code p1780 is by checking the battery’s performance. This can be done by connecting a multimeter to its positive and negative terminals. If the multimeter reads a voltage less than 12.6, the battery is bad and needs to be replaced to fix the p1780 code.

6. Underdrive clutch system has malfunctioned

The underdrive clutch is responsible for transmitting a speed less than the engine’s speed to the driven shaft. As such, if it breaks, your car will switch into overdrive resulting in code p1780 being shown. This clutch can get damaged due to overheating and exposure to water. When it is bad, you will notice that it starts to slip. The bad news is that a malfunctioned underdrive clutch cannot be repaired. However, you can replace it at home, saving you the cost of hiring a mechanic. It is a lengthy and hard process, though.

How much does it cost to fix code p1780 in your Ford?

The cost of fixing this code depends on your location, the affected part, and the car’s model. But generally, the average price normally ranges between $75 and $150 an hour. In total, you could end up paying up to $1,000 for the service. High price, right? This tells you that you should take all precautions to avoid draining your pocket, such as regularly taking your car for maintenance. Your Ford’s manual should give you the timeline for when you are supposed to take the car for servicing.

To wrap up,

Code p1780 is one of the many codes indicating a problem with your Ford. This code normally tells you that the TCS, the PCM, or the underdrive clutch has run into issues that result in the transmission switching into overdrive. It can be caused by poor connections in the transmission circuit, faulty batteries, defective or detached cables, and malfunctioning PCM. The overdrive issue is not usually bad when driving on flat roads but can be a headache when driving up or down the heels. So, make sure you fix what is causing it to have a pleasant drive.

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