What is the P1778 Engine Code?

What is the P1778 Engine Code

Getting the P1778 engine code on your Nissan vehicle may be a bit scary when you encounter it for the first time, but thankfully, it can be easily resolved with the help of an experienced technician. If you’re experienced in car repairs, you might even be able to take care of it yourself!  

Before driving down to the car shop to get it fixed, it might be a good idea to learn a little more about the code, what it means, and how to diagnose it properly. Even the most expert technicians can make small mistakes, which could cost you thousands of dollars a few months down the road, so having that extra knowledge will certainly help you if you run into a similar problem in the future. 

What Does the P1778 Code Mean? 

The P1778 Nissan code refers to an issue with the step motor function of your car. It will pop up on your on-board diagnostic (OBD) scanner when your Nissan’s engine or powertrain control module receives information from the transmission control module about a possible malfunction in your car’s step motor. 

The step motor is responsible for regulating your vehicle’s idle speed by controlling the air flowing into the engine and keeping the number of revs (revolutions per minute) above the minimum required to maintain the current speed. It is worth noting that the step motor is one of those engine parts that malfunction more often than others. 

So, if you see the red “check engine” light goes off on your dashboard and your OBD scanner shows the P1778 code, which refers to a faulty step motor function, you can breathe easy. Things could have turned out to be much worse. 

Finally, keep in mind that the P1778 code is exclusive to Nissan vehicles. When driving a car of another make, your step motor function issues will be indicated by a different engine code. 

Possible Causes of the P1778 Code 

Merely seeing the P1778 engine code on your OBD scanner doesn’t necessarily mean that your step motor is completely broken and requires replacement. Some of the other causes behind this code include an open or shorted harness that keeps your step motor in place. 

It could also indicate that there is an electrical problem inside your engine, and that the step motor’s circuit wiring or connection to the engine control module (ECM) is busted. The P1778 Nissan code could also mean an issue with your transmission control module connection to the step motor, in that it does not relay the information from that part of your engine to the ECM. 

Of course, a broken step motor is certainly a possibility, as well. As we mentioned earlier, these parts are quite fickle and in some cases, they break routinely. Thankfully, step motors are not too expensive and their replacement does not take up too much time. 

One of the worst-case scenario explanations for the P1778 code is a failure of your continuously variable transmission (CVT), which is a type of automatic transmission system utilized in many modern cars. If that turns out to be the reason behind this code, then you might be forced to replace your CVT, which could cost you quite a bit of money. 

P1778 Code Symptoms 

There are no clear-cut symptoms of the P1778 code, besides the lighting up of your malfunction indicator light (MIL). Of course, some symptoms, such as electrical issues or problems with gear shifting, might be related to this code, but they are all dependent on what caused your step motor issue in the first place. The only universally-found symptom for the Nissan P1778 code is the MIL. 

How Much Does It Cost to Diagnose the P1778 Engine Code? 

The diagnosis of a P1778 engine code at a car repair shop is not too expensive by itself. It usually takes about one hour of work, so depending on the establishment you frequent, your bill would amount to about $75-$150. 

Can I Fix the P1778 Code Myself? 

The answer to this question depends on your level of experience with fixing cars and engine maintenance. As opposed to changing the oil or wiper fluid, investigating the P1778 could prove too difficult for a beginner, especially if it turns out that the underlying cause is a serious one. 

If you do decide to investigate your P1778 Nissan code, make sure to double-check the following things: 

  • All the connectors and wiring 
  • Step motor voltage 
  • Step motor resistance 

The Bottom Line 

So, there you have it – the P1778 engine code, explained. Since you’re looking up advice for this code, it can be safe to assume that you’re a Nissan owner. If you don’t have a trusted car repair shop to handle that issue, keep in mind that you are best off looking for places that specialize in Nissans – this is where you’ll get the best service, minimizing the risk of the technicians overlooking certain key details simply because they don’t have as much experience with this make. 
Finally, reading engine codes in your car is impossible without an OBD scanner. If you don’t already keep one in your glove compartment, it’s about time you change that. Head over to OBD station for a comprehensive collection of reviews and articles that will help you choose the best scanner for your car!