Symptoms of a Bad or Failing Transmission Speed Sensor

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Cost of Replacing a Bad or Failing Transmission Speed Sensor

Common signs include harsh or improper shifting, cruise control not working, and the Check Engine Light coming on. Our certified technicians can come to you and diagnose the problem. You will receive a $30 credit towards any follow-up repairs that result from the diagnostic. Following are example prices for Transmission Speed Sensor Replacement. Click on the button below to get an upfront quote for your car.

Cars Estimate Parts Cost Labor Cost Savings Average Dealer Price
2014 GMC Savana 1500 $112 $41.64 $70.00 25% $149.14
2014 Toyota Tundra $116 $46.41 $70.00 24% $153.91
2003 Mitsubishi Outlander $217 $146.53 $70.00 14% $254.03
2003 BMW 325Ci $237 $89.88 $147.00 24% $315.63
2007 Mercedes-Benz B200 $297 $121.84 $175.00 24% $390.59
2009 Audi S6 $293 $83.49 $210.00 27% $405.99
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How to Diagnose a Bad or Failing Transmission Speed Sensor?

transmission speed sensor

The transmission speed sensors are used to calculate the actual gear ratio of the transmission while in use. There are generally two speed sensors that work in conjunction to provide accurate transmission data to the vehicle’s powertrain control module. The first is known as the input shaft speed (ISS) sensor. As described, this sensor is used to monitor the speed of the transmission’s input shaft. The other sensor is the output shaft speed (OSS) sensor. If either of these two sensors falls out of alignment or experiences electrical issues, it impacts the operation of the entire transmission.

After registering data, the two transmission speed sensors, also commonly referred to as a vehicle speed sensors (VSS), send data to the powertrain control module (PCM), which compares these two inputs and calculates which gear the transmission should engage for efficient driving. The actual gear ratio is then compared to the desired gear ratio. If the desired gear and the actual gear do not match, then the PCM will set a diagnostic trouble code (DTC) and illuminate the Check Engine Light.

Should either or both of these speed sensors fail, you may notice one or more of the following 3 issues:

1. Harsh or Improper Shifting

Without a valid speed signal from these sensors, the PCM will not be able to correctly control the shifting of gears within the transmission. This may cause the transmission to shift roughly or more quickly than normal. It's also common that a problem with these sensors can impact the shift timing, extending the interval between transmission shifts. An automatic transmission is hydraulically controlled and designed to shift smoothly. When the transmission shifts hard, it can damage internal components including valve bodies, hydraulic lines, and in some cases mechanical gears. If you notice your transmission is shifting harshly or roughly, you should contact a local ASE certified mechanic as soon as possible.

2. Cruise Control Does Not Work

Since the transmission speed sensors monitor the input and output shaft speed, it also plays a part in monitoring the cruise control. When the sensors fail to deliver accurate data to the onboard computer on your car, truck, or SUV, the powertrain control module (PCM) will send an error code to the vehicle’s ECU. As a safety precaution, the ECU will shut down the cruise control and render it inactive. If you notice that your cruise control does not engage when you press the button, contact a mechanic so they can inspect the vehicle and determine why the cruise control is not working. It may be due to faulty transmission speed sensors.

3. Check Engine Light Comes On

If the signals are lost from the transmission speed sensors, the PCM will set a DTC and illuminate the Check Engine Light on the vehicle dashboard. It also can indicate an increase in tailpipe emissions surpassing acceptable limits for environmental contaminants from motor vehicles.

In any case, if you notice that the Check Engine Light comes on, you should contact a local mechanic to scan the error codes and determine why the Check Engine Light is illuminated. Once the problem has been fixed, the mechanic will reset the error codes.

If the problem rests with the speed sensors, depending on your particular transmission, the professional ASE certified mechanics may be able to replace the sensor. Some speed sensors are internal to the transmission and will require the transmission to be removed from the vehicle before the sensors can be replaced.

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Recent Transmission Speed Sensor Replacement reviews

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YourMechanic Transmission Speed Sensor Replacement Service

Average Rating

4.6/5

Number of Reviews

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Rating Summary
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Jeffrey

24 years of experience
683 reviews
Jeffrey
24 years of experience
Though I was not at home when he arrived My wife and daughter gave Him High praise for his punctuality and professionalism ... Also, je was able to solve the check engine light problem which has plagued My daughter's car for years now... Thanks So very much... I'll be using your services again soon... 
1997 TOYOTA AVALON - TRANSMISSION SPEED SENSOR - CHARLOTTE, NORTH CAROLINA

Maxwell

15 years of experience
389 reviews
Maxwell
15 years of experience
A+++ Workmanship. Very detailed and resolution oriented.
2001 LEXUS RX300 - TRANSMISSION SPEED SENSOR - CONROE, TEXAS

Chris

13 years of experience
397 reviews
Chris
13 years of experience
Awesome! Good guy! Reliable
1999 DODGE RAM 1500 VAN - TRANSMISSION SPEED SENSOR - SAN FRANCISCO, CALIFORNIA

Duane

22 years of experience
323 reviews
Duane
22 years of experience
Duane was a few minutes early, very knowledgeable of my transmission\speed sensor problem, explained my options in detail, & test drove the repaired car - all within one hour for under $300! I can't imagine how much more transmission service at a dealer would've cost me. I booked another appointment with Duane for transmission fluid service\maintenance to replace the burned fluid.
2012 HYUNDAI ELANTRA - TRANSMISSION SPEED SENSOR - LA MESA, CALIFORNIA

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