Need car parts? Select your vehicle
Reading Time: 10 minutes
Summary
  • The P0705 code is defined as “Transmission Range Sensor Circuit Malfunction (PRNDL Input)
  • A P0705 code can be caused by a malfunctioning transmission range sensor (or PRNDL input), faulty wiring, bad shift linkage, or a faulty PCM or TCM.
  • Some symptoms of the P0705 code include an illuminated check engine light, rough or delayed shifting, or other gear-shifter-related symptoms.

A P0705 code is a generic powertrain code that can be triggered in select vehicles built from 1996 onward. This OBD-II code may present common symptoms in different types of vehicles, but diagnosis and repair may vary for each specific make and model.

What Does the P0705 Code Mean?

Diagnostic trouble code (DTC) P0705 code stands for “Transmission Range Sensor Circuit Malfunction (PRNDL Input).” It is triggered when the transmission range sensor cannot send data or provides erroneous input to the transmission control (TCM) or powertrain control (PCM) modules.

The transmission range sensor may also be called the neutral safety switch or PRNDL input. Located outside the transmission box or on the valve body, its job is to communicate the current gear selection or shift lever position with the TCM or PCM.

To learn more about how transmission range sensors work, you can read our in-depth explanation here.

a car's neutral safety switch
The transmission range sensor or neutral safety switch communicates the current gear selection or shift lever position with the TCM and PCM.

What are the Possible Causes of the P0705 Code?

There are two scenarios that could cause a vehicle’s OBD-II system to log a P0705 code. The first is when the TCM and PCM do not receive any information from the transmission sensor at all.

The second is when these modules receive an irrational input from the sensor.

An example could be if the vehicle is running at 70 mph, but the sensor signals the TCM that the car is in park. Likewise, this diagnostic trouble code will trigger if the sensor sends signals that indicate that the vehicle is in multiple gears at the same time.

Here are the common problems that can cause missing/faulty readings from the transmission range sensor:

  • Malfunctioning transmission range sensor (PRNDL input)
  • Issues with the transmission range sensor circuit, such as damaged wires or poor connections
  • Defective valve body
  • Defective shift linkage
  • Faulty TCM or PCM

What are the Common Symptoms of the P0705 Code?

A P0705 trouble code may cause performance problems that would be noticed by the driver. Below are some signs that you should look out for:

  • Check Engine Light is on or blinking
  • Rough or delayed shifting
  • Failure to put the vehicle into gear
  • Erratic dash indicators (PRNDL)
  • Reverse lights don’t switch on
  • Vehicle starts with the gear selector in a position other than park or neutral

Occasionally, a malfunction in the transmission range sensor circuit may occur without any adverse effects that affect the drivability of your vehicle.

How to Diagnose the P0705 Code

There are a lot of possible causes that could trigger the P0705 code, so diagnosis can get a little tricky especially if you’re not very car-savvy. This is why most people just leave the job to their mechanic.

However, you can still do the job yourself with the help of a detailed guide. Below is a helpful video with more information to help you diagnose the P0705 code:

How to Fix the P0705 Code

Disclaimer: Due to the wide variability in vehicle makes and models, as well as other factors, the following information must not be construed as complete or the only definitive way to address a particular issue. Instead, the following content merely attempts to give you a better idea of what a do-it-yourself approach to the issue might involve. You are encouraged to find more technical resources regarding the subject or take your vehicle to a professional technician for the best results.

There’s no one-size-fits-all solution for the P0705 code—just like with most OBD-II codes. Most people simply take their cars to their mechanics and leave the job to them. However, if you feel confident in your DIY skills or are looking to learn more about auto repair, here are some fixes you can try yourself.

See also  P0141 Code: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)

Double Check the Code

Use a scanner to double check the code and confirm if there are other underlying issues. If there’s a persisting error, try and resolve it by checking and replacing the transmission fluid if necessary. As with any code, read and record all DTCs and freeze frame data, then clear the code and drive the vehicle at the same speed and load, etc. to try and recreate the code. This is what mechanics do.

You can also inspect the linkage between the gearshift lever and the gear shifter, since they may need adjustment.

Adjust the Transmission Range Sensor

You can try readjusting the transmission range sensor to clear the P0705 code. To do so, you’ll need a transmission range sensor alignment tool and to follow the steps below:

  • Step 1: Disconnect the transmission range (TR) sensor, electrical connector, and the selector lever cable.
  • Step 2: Loosen the TR sensor by removing the manual control lever and loosening the TR sensor bolts.
  • Step 3: Use the transmission range sensor alignment tool to align the TR sensor and to tighten the bolts to 10 Nm.
  • Step 4: Install the manual control lever and tighten its bolt to 30 Nm.
  • Step 5: Adjust the manual control lever to TR sensor D position.
  • Step 6: Lastly, connect the selector lever cable and the TR sensor electrical connector together.
, P0705 Code: Transmission Range Sensor Circuit Malfunction (PRNDL Input)

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: One easy way to adjust the transmission range sensor is to put the vehicle in reverse and look at the back-up lights. If they’re not on, adjust the sensor until you see them come on. That will usually get it close enough.

Visual Inspection

Check the transmission range sensor circuit for any corroding or disconnected wires. More often than not, these are enough to cause the code, so fixing these  issues should get rid of the error.

Replace the Transmission or Engine Control Modules

If the code still persists even after trying the fixes above, your last resort should be replacing the transmission control module (TCM) or the engine control module (ECM). To replace the TCM, follow the steps below:

  • Step 1: Buy a replacement TCM that’s compatible with the year, make, and model of your car. Not all of these are plug and play, so you might need some programming done.
  • Step 2: Open the hood and locate the TCM. It’s often located near the transmission with wiring attached that connects it to the engine control module.
  • Step 3: Remove the old TCM by unscrewing the bolts that hold it in place. Then remove the wires attached to the TCMs data port.
  • Step 4: Install the new TCM by following the steps above in reverse.

As for the ECM, here’s step-by-step guide on how to properly replace it:

  • Step 1: Disconnect the battery from the car at least 15 minutes before installation.
  • Step 2: Locate the ECM by consulting your owner’s manual, but it’s usually located in the engine compartment.
  • Step 3: Unbolt the screws holding the ECM in place.
  • Step 4: Remove the old ECM and replace it with the new one.
  • Step 5: Reconnect the batteries and start the vehicle to confirm if everything is functioning.
See also  P0403 Code: Exhaust Gas Recirculation “A” Control Circuit Malfunction

It’s important to note that different vehicles may involve different fixes. For example, replacing the transmission range sensor has been confirmed to work in fixing a P0705 code on a 2011 Ford F-150, XL 5.0L, V8, but doing the same thing may not work for your vehicle.

Other Tips to Help You Fix P0705

On vehicles where the Transmission Range sensor is integrated with the Transmission Control Module, some programming may be required, so don’t try that on your own. One way or another, you need to find out everything you can about how your particular TR sensor works and how it is wired. And if that isn’t enough, sometimes the TR sensor is very difficult to access, particularly on front wheel drive vehicles.

Thus, when doing any DIY work on your vehicle, always make sure to consult repair manuals and credible online guides. When you try to “wing it,” you can make a lot of problems for yourself that you didn’t have before.

You can get an ALLDATA single-vehicle subscription, which should give you the information you need for this and any other future repairs your car may need.

An In-Depth Look at How Transmission Range Sensors Work

To begin with, it bears mention that the automatic transmissions and transaxles in new vehicles, while still mostly hydraulic, have solenoids that facilitate transmission shift functions, and those solenoids are controlled by the vehicle’s Powertrain Control Module (PCM) or by a Transmission Control Module (TCM). The Engine Control Module (ECM) only controls the engine; a vehicle with an ECM and an automatic transmission will have a stand alone TCM. Jeep Cherokees used this setup beginning in the 80s.

On newer vehicles, the ECM and TCM will share pertinent information on the network bus. A PCM controls both the engine and the transmission, but as the demands on the PCM increased with each new model year, manufacturers separated engine and transmission controls into separate modules, thus the TCM.

How Transmission Range Sensors Developed

Okay, whenever there’s a computer controlling the transmission shift points and line pressure, that computer needs to know where the gear selector is at all times. So how does it do that?

Very early model Fords without electronic transmissions only need to know when the selector is in Park or Neutral, so the ECM (Ford referred to it then as a “Processor”), is watching the starter solenoid wire between the ignition switch and the neutral safety switch, which is where the Transmission Range Sensor is on newer vehicles.

When the transmission is in Park or Neutral, the ECM will detect a ground path through the starter solenoid – in any other gear it won’t. That information is used for idle speed control and other load-related functions on those vehicles.

But as solenoids and speed sensors took root in transmissions and transaxles in the 1980s, it became clear that the PCM needs to know exactly where the gear selector is at all times. And the engineers decided how best to do it on their various platforms; it is handled several different ways. We don’t have time to discuss them all, but here are a few.

How Transmission Range Sensors Operate on Different Platforms

ford digital transmission range sensor signal
The Ford digital transmission range sensor signal works like this. Notice the four switches, with each switch either being on (1) or off (0) in groups in each gear range. The TCM/PCM uses a binary code system to determine the selected range on a sensor like this one. The connector in the photograph, if you’ll notice, has corroded pins, which can cause the TR sensor’s signals to be incorrectly read by the TCM/PCM. | Image Source: Richard McCuistian

The Transmission Range Sensor is usually mounted on and keyed to the shift rail, which rotates through shifter detents when you make your gear selection – detents being those places where you can feel the shifter “click” through the gears on the way to the position you want and finally into the one you have selected.

The Transmission Range Sensor is usually mounted on and keyed to the shift rail, which rotates through shifter detents when you make your gear selection – detents being those places where you can feel the shifter “click” through the gears on the way to the position you want and finally into the one you have selected.

Richard McCuistian, ASE Certified Master Automobile Technician
  • Mid-80s Ford Tauruses used a transmission range sensor that operates similar to a throttle position sensor – it receives reference voltage and ground from the PCM and has a signal wire returning shift rail position to the PCM. A graph of this voltage signal looks like stair steps; the PCM knows the gear selector position by the voltage level on the signal wire. That signal could get “scratchy” and give the PCM bad information, but on that system, it would take a near total failure of the sensor before the PCM could detect it.
  • Later model Fords used a digital transmission range sensor with four on-off switches. This kind of signal is much easier for a computer to process, because computers are basically binary code readers, and the on-off switches provide a four digit binary code. This arrangement is very reliable and gives almost no trouble; you can recognize this kind of Range Sensor due to the large number of wires in the connector (usually 12).
  • The 2012 Camry has a very simple arrangement whereby the transmission range Sensor has a single system voltage feed to the sensor, and in each selected gear feeds that voltage out to the PCM on a different wire. It’s fairly easy to understand how the PCM can determine when the Range Sensor or its circuits have malfunctioned on a setup like this. The computer expects to see a brief voltage flash at each position followed by a steady voltage feed from the gear selected. This Transmission Range Sensor uses 8 wires, one voltage feed in and 7 discrete feeds out to the PCM.
  • The newest vehicles will have the transmission control module mounted in or on the transmission or transaxle and the transmission range sensor will be integrated into the computer itself.
See also  P2096 Code: Post Catalyst Fuel Trim System Too Lean (Bank 1)

This could go on for pages, but you get the point. Not all transmission range sensors work the same way, even though they do the same job. Neutral safety and backup light functions are obviously tied to switch position as well.

Where To Get a New Transmission Range Sensor for Your Vehicle

Ignoring a P0705 code is never a good idea, especially because a faulty transmission range sensor can make it hard for you to shift gears. This can increase your risk of getting into a traffic accident, so it’s best to replace your PRNDL input as soon as possible. Luckily, you can conveniently order a new transmission range sensor here at CarParts.com.

With an easy-to-use interface, CarParts.com takes out all the hassle of buying a quality replacement part. You can rest assured that we only source our transmission range sensors from the best manufacturers in the industry. We also provide accurate and detailed fitment information, so you can find a part with the perfect fit for your vehicle.

Don’t wait for your vehicle to get worse. Fix the issues setting the P0705 code by ordering a new transmission range sensor here at CarParts.com today!

Products Mentioned in this Guide

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

headlights and components
Subscribe
Notify of
guest
1 Comment
Inline Feedbacks
View all comments
Formula one

An important and wonderful topic , it was a good help to me and I benefited a lot from it .
Thank you very much ma’am .
More brilliance and creativity

View all Questions & Answers

expand_more
CarParts.com Answers BE PART OF OUR COMMUNITY: Share your knowledge & help fellow drivers Join Now