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OBD2 code P0705: Meaning, causes and diagnosis

 

P0705 is a very common transmission-related fault code. In simple terms, it means that the vehicle’s computer cannot know which gear you have selected, which can have some real consequences on driving.

Although P0705 is a generic code (it has the same definition for any vehicle manufactured since 1996), it is most commonly seen on Nissan, Toyota, Mercedes, and Land Rovers.


P0705 Definition: TRS – Circuit Malfunction

This is the meaning of P0705, divided into two main parts:

TRS

The transmission range sensor (TRS) is responsible for telling the transmission control module (PCM) or transmission control module (TCM) what gear the vehicle is in. For this article, we will use the term PCM as the preferred term

Perhaps the most common solution for P0705 is a new TRS. Typically, you’ll find the TRS bolted to the transmission, making it easy to find and replace. Unfortunately, in some newer vehicles, it may be located inside the transmission, making replacing it at home almost impossible.

Circuit malfunction

A circuit malfunction means that the TRS is not sending the proper signal to the PCM. There may be no signal, or the voltage value may not be within the range of any gear. In either case, P0705 will be stored in the PCM memory, and the check engine light will come on.


P0705 Symptoms

The symptoms associated with P0705 will vary depending on how the PCM reacts to not receiving a signal from the TRS.

These are the most common symptoms:

  • Won’t start (the neutral safety switch doesn’t know what gear the transmission is in). Check if it starts in neutral.
  • Strange shift patterns (usually early shifts)
  • Decreased MPG
  • The delay between selecting a gear and engaging the transmission
  • There are no reversing lights

P0705 Causes + Diagnosis

P0705 Diagnostic

If your vehicle has an internal TRS, there’s not much you can do to fix it at home. On the other hand, if it is external, here are some general steps you can follow.

You will have to find the shift linkage on the transmission.

Inspect TRS

Inspect the TRS to see if there are any obvious problems. First, take a look at where the wiring harness plugs in. Make sure it is still plugged in properly. Make sure there are no bent or displaced pins on the sensor.

If it’s plugged in securely and the pins look good, it’s time to move on to the wiring harness. Make sure it is not burned, cracked, shorted, or damaged. This is a common problem when you have P0705.

If your vehicle starts in gear but not in neutral, the TRS could be out of alignment. There should be a neutral alignment mark

TRS Replacement

Aside from a wiring or alignment issue, there isn’t much else that could cause P0705 other than replacing the TRS.

Assuming the TRS is on the outside of the transmission, replacing it is usually pretty easy. Some are more lenient than others when it comes to aligning them; Follow the instructions and alignment marks, and you should have no problems.


Conclusion

A bad TRS is usually the cause of P0705. The location of that TRS (inside or on the transmission) is going to dictate whether you can do anything about it at home or not. Good luck!

 

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