Chevrolet Blazer Transmission Speed Sensor Guide: 2019-2022
Learn to identify the symptoms of a failing transmission speed sensor in your Blazer and what it means for your vehicle's performance.
- Your Blazer uses both ABS wheel speed sensors and transmission speed sensors; a P0500 code often points to the transmission output sensor.
- Symptoms like harsh shifting can also be caused by known transmission issues covered by TSB 20-NA-136, so proper diagnosis is key.
- A quality aftermarket brand like Standard Ignition offers a reliable and budget-friendly fix for this common problem.
- Replacement is a simple DIY job for many, involving a single bolt and electrical connector on the outside of the transmission.
Understanding Speed Sensors in Your 2019-2022 Blazer
When discussing speed sensors, it's easy to get confused. Your Blazer has two main types. First, there are four ABS Wheel Speed Sensors, one at each wheel. 🎬 Watch: How to replace a Blazer ABS wheel speed sensor These primarily manage the anti-lock brakes and traction control systems, but they also provide speed data to the speedometer. Second, your automatic transmission has its own sensors: an Input Speed Sensor and an Output Speed Sensor. The part discussed here is the transmission output speed sensor, which is critical for proper gear shifting. A failure in this sensor can cause problems that feel very serious but are often fixed with a simple, inexpensive part.
Symptoms of a Bad Transmission Speed Sensor
A failing transmission speed sensor sends bad information to your Blazer's computer, leading to noticeable problems. Here are the most common signs:
- Harsh or Erratic Shifting: The transmission may slam into gear, hesitate between shifts, or refuse to shift into a higher gear.
- Check Engine Light: A faulty speed sensor will almost always trigger the check engine light. You may find diagnostic trouble codes (DTCs) like P0500, P0501, or P0720 🎬 Watch: Learn about common causes and fixes for code P0720 stored in the computer.
- Incorrect or Dead Speedometer: The speedometer might jump around, show the wrong speed, or not move at all.
- Cruise Control Won't Work: The cruise control system relies on a steady speed signal to function. If the signal is gone, cruise control will be disabled.
Known Transmission Issues
The 9-speed transmission in 2019-2021 Blazers is known for some issues. GM released a Technical Service Bulletin (TSB 20-NA-136) for problems like shuddering, hesitation, and hard shifting. 🎬 See if a transmission shudder fix in a tube actually works These symptoms are very similar to a bad speed sensor. If you experience these issues, it's important for a mechanic to properly diagnose whether the cause is a simple sensor or a more complex internal transmission problem.
Choosing the Right Aftermarket Part: Standard Ignition
When replacing a sensor, you don't always need to buy the expensive OEM part from the dealer. For a common part like a transmission speed sensor, a quality aftermarket brand is a smart choice. Standard Ignition (also known as Standard Motor Products or SMP) is a well-respected manufacturer that has been making automotive electronics for decades. They produce parts that meet or exceed original equipment standards and are a reliable, cost-effective option for your Blazer.
Cost to Replace a Blazer Transmission Speed Sensor
| Part Type | Estimated Cost |
|---|---|
| New OEM (GM Genuine Parts) | $40 - $70 |
| New Aftermarket (Standard Ignition) | $11.46 |
| Shop Labor | $100 - $150 |
Cost estimates are approximate and can vary by location and supplier. The aftermarket price is based on current inventory.
A Note on Labor Costs
Some online estimators show very high labor costs for this repair. This may be because they confuse it with a more difficult job, like replacing a sensor located inside the transmission. For an externally mounted sensor, the replacement is typically quick and should take less than an hour of a mechanic's time.
Frequently Asked Questions
Where is the transmission speed sensor located on a 2019-2022 Blazer?
The transmission input and output speed sensors are typically mounted externally on the transmission case. You will need to safely raise the vehicle to access them from underneath. A repair manual or vehicle diagram can help you pinpoint their exact location on your specific transmission.
Can I drive my Blazer with a bad transmission speed sensor?
Yes, but it's not recommended for long. The vehicle will likely go into a "limp mode" with harsh shifting and an unreliable speedometer. This can be unsafe in traffic and puts extra stress on your transmission.
Is this a difficult DIY job?
For someone with basic mechanical skills, this is a very feasible DIY repair. It usually involves safely lifting the vehicle, locating the sensor, disconnecting a wire, removing one bolt, and swapping the part. The most important part is correctly identifying the output speed sensor.
Are there any recalls for this part?
No, there are no specific recalls for the transmission speed sensors on the 2019-2022 Chevrolet Blazer. There was a recall for a transmission oil leak (N202313440) on 2019-2020 models and a wheel speed sensor recall on other GM trucks and SUVs, but the Blazer was not included in the latter.
Helpful Videos
Technical Specifications
OEM Part Numbers: 24298199 24295280 24284707 24278523
Typically a 2-terminal magnetic sensor that mounts to the exterior of the transmission housing.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Chevrolet Blazer:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Understanding Speed Sensors in Your 2019-2022 Blazer
- Symptoms of a Bad Transmission Speed Sensor
- Known Transmission Issues
- Choosing the Right Aftermarket Part: Standard Ignition
- Cost to Replace a Blazer Transmission Speed Sensor
- A Note on Labor Costs
- Frequently Asked Questions
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