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P0727 is a diagnostic trouble code (DTC) for "Engine Speed Input Circuit No Signal". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
If the P0727 code is stored, it’s a sign that the vehicle’s PCM has received a signal regarding the engine speed from the engine speed input sensor.
The signal that triggers P0727 means that the engine speed input sensor is erratic, irrational or incorrect in some other way. Without an input speed signal that can be relied upon, the transmission in your vehicle can’t provide a useful shifting strategy.
Although it may differ a bit between manufacturers, the majority of PCMs are programmed to anticipate engine speeds to gradually increase until a shift point is reached (engine speed is expected not to exceed output speeds up until this point as well).
It’s when the input speed doesn’t increase gradually or the PCM doesn’t receive a signal (or an erratic one) that the P0727 code will be stored. The Check Engine Light may come on too, but that’s not always the case. With some models, it takes more than one failure cycle before the light comes on.
More often than not, the problems that trigger the P0727 code are caused by either a defective transmission output speed sensor or a faulty engine input speed sensor. However, there could be other reasons too, like:
If your vehicle stores a P0727, you’ll probably find out because of harsh shifting. Some of you may actually be unable to shift altogether. Another common symptom associated with this code is a loss of fuel economy.
It also isn’t unusual for the speedometer to fluctuate uncontrollably or even completely stop working. When you decide to park, the engine might stall on you. A vehicle that is reporting P0727 will occasionally also make it clear by having the engine misfire, sag or hesitate. If all that isn’t enough, the Check Engine Light should come on.
This code is often associated with one regarding the output speed sensor.
Despite all of the above, in some uncommon circumstances, drivers notice no adverse symptoms whatsoever.
Your mechanic will begin by using a code reader to take stock of what is ailing your vehicle. They might also use an oscilloscope. With these tools, the mechanic will measure engine input speeds.
They’ll most likely inspect the related wiring as well as other electrical components involved. Aside from checking for areas where they have become frayed, are disconnected or are otherwise damaged, the mechanic is also looking for wiring and connectors that show signs of transmission fluid or engine oil leaking on them.
After that, the scanner will be connected to the diagnostic connector to record freeze frame data which can be used later.
One common mistake is thinking that this code relates to a vehicle speed malfunction, engine misfire, driveline malfunction or fuel delivery problem.
If your vehicle can’t properly shift, it’s not going to be much good to you. Even if you’re one of the lucky ones who doesn’t have any symptoms, that could be short-lived. You’re better off taking it to a mechanic ASAP.
The following may fix the P0727 code:
While it’s true that the problem could also be due to a faulty PCM, this is incredibly rare.
YourMechanic has certified mobile mechanics who will drive to your home or office to assess and repair your vehicle. You can receive a quote and book an appointment online or talk to a service advisor by calling. 1-800-701-6230.