What happens when a transmission range sensor goes out?

The transmission position sensor, also known as the transmission range sensor, is an electronic sensor that provides a position input to the Powertrain Control Module (PCM) so that the transmission can be properly controlled by the PCM according to the position commanded by the sensor.

Over time, the transmission range sensor may begin to fail or wear out. If the transmission range sensor fails or suffers a malfunction, there are a number of symptoms that could appear.

1. Car does not start or cannot move

Without a proper Park/Neutral position input from the transmission range sensor, the PCM will not be able to crank the engine over for starting. This will leave your car in a situation where it cannot be started. In addition, if the transmission range sensor has completely failed, the PCM will not see any gear command input at all. This means that your vehicle will not be able to move at all.

2. Transmission goes into different gear than selected

There could potentially be a mismatch between the gear selector lever and the sensor input signal. This would cause the transmission to be in a different gear (controlled by the PCM) than the one selected by the driver using the shift lever. This could lead to unsafe operation of the vehicle and could likely become a traffic hazard.

3. Vehicle goes into limp mode

On some vehicles, if the transmission range sensor fails, the transmission can still be mechanically placed into gear, but the PCM will not know which gear that is. The transmission will be hydraulically and mechanically locked into one specific gear for safety, a situation known as limp mode. Depending on the manufacturer and the particular transmission, limp mode could be 3rd, 4th, or 5th gear, as well as Reverse.

Any of these symptoms necessitate a visit to the shop. However, instead of taking your vehicle to a mechanic, the technicians at YourMechanic come to you. They can diagnose whether your transmission range sensor is bad and replace it if necessary. If it turns out to be something else, they’ll let you know and diagnose the issue with your car so it can be repaired at your convenience.

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Your car’s transmission contains many sophisticated parts that must work in synchronicity to power your vehicle forwards. When your vehicle starts to experience transmission problems, the issue could be the result of a failing transmission position sensor. Using specialized diagnostic tools, a transmission repair specialist in Sacramento can pinpoint the source of your vehicle’s transmission problems. To help you figure out what is going wrong with your transmission system, here is a look at the common signs of a failing transmission position sensor.

Car fails to move out of park.

When your vehicle is unable to shift out of neutral or park, this is a clear indication that there is a serious problem somewhere in the transition system. A failing transmission position sensor may no longer send the right signals to the Powertrain Control Module, or PCM. Without signals from the position sensor, the PCM will no longer know when to shift the transmission’s gears out of park into a moving gear.

Transmission shifts into the wrong gear.

The transmission position sensor and PCM work together to allow the automatic transmission to choose the right gear for various speeds of travel and driving conditions. When your transmission shifts into the wrong gear, you may notice that your engine seems to stall out or rev unexpectedly. If your transmission is continually mismatching its gear selection and gear ratios, you may want to ask your mechanic to check on the condition of your transmission position sensor.

Vehicle becomes locked in a single gear.

Many modern vehicles are equipped with failsafe devices, which prevent the transmission from shifting gears if a mechanical or electrical problem is detected. If your transmission position sensor is failing, your transmission may become locked in an unchanging gear. This condition is known as limp mode, and a car that has gone into limp mode is suffering from severe transmission issues. Fortunately, your mechanic will be able to restore your transmission position sensor to proper working condition and return your transmission to full functionality.

If you hear a clicking sound instead of the familiar roar of your engine when turning the ignition key, your car’s transmission range switch or sensor may have failed

Have you ever tried to start your car while it’s running or is in gear?

It may make a terrible sound, but it’s impossible to do thanks to a safeguard built into your vehicle called a transmission range switch or transmission range sensor (TRS).

Sometimes called a neutral safety switch, the TRS is an electrical switch that tells your vehicle’s powertrain control module what gear your transmission is in when you turn the ignition key to the “on” position. Its function is to prevent you from attempting to start your engine while it’s running unless the transmission is in the ‘neutral’ or ‘park’ position, or if your car has a manual transmission if you depress the clutch pedal.

Like any mechanical component, the TRS can become faulty through wear and tear over time, and that can lead to significant problems with your transmission.

Testing the TRS is an oft-overlooked troubleshooting step that many mechanics neglect when attempting to diagnose transmission problems. If your TRS is failing or has failed, when you turn the ignition key, you’ll likely hear a clicking sound instead of the familiar roar of your engine as it turns over.

Faulty Transmission Range Switch Warning Signs
If your car’s TRS is on the fritz, either you won’t be able to start your car or the “service engine soon” light on your dashboard will remain lit. Other warning signs of a faulty transmission range switch include your car starting in the wrong gear, the transmission struggling to change gears or gears slippage.

If you can start your engine, drive it to a Mister Transmission location near you and have it inspected by one of our experienced technicians, otherwise you run the risk of not being able to restart your vehicle later and may have to call a tow truck.

Do you have questions about your car’s transmission range switch? Talk to an expert Mister Transmission technician. Find your nearest location.

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