Chevrolet Blazer Manifold Absolute Pressure (MAP) Sensor Guide: 2019-2021
Understanding the signs of a failing MAP sensor and how to choose the right replacement for your Blazer.
- A failing MAP sensor on a 2019-2021 Blazer commonly causes a check engine light with code P0106, rough idle, and poor fuel economy.
- Replacement is an easy, 15-minute DIY job for most owners, requiring only basic tools.
- Premium aftermarket brands like Bosch, Delphi, and NGK offer OEM-quality without the dealership price tag.
- Before replacing the sensor, consider that a dirty throttle body can sometimes trigger a false MAP sensor code.
Understanding MAP Sensor Failure in Your Blazer
The Manifold Absolute Pressure (MAP) sensor in your 2019-2021 Chevrolet Blazer is a critical component for engine efficiency. When it fails, the engine's computer receives incorrect information about engine load, leading to a variety of performance issues. A bad sensor can cause the wrong air-fuel mixture, which may result in poor fuel economy, rough idling, and even engine stalling. Failure is often caused by exposure to extreme heat, engine vibrations, or contamination from engine byproducts over time.
Symptoms of a Bad MAP Sensor
If your Blazer's MAP sensor is failing, you will likely notice one or more distinct symptoms. The most obvious sign is the Check Engine Light illuminating on your dashboard. You may also experience:
- Poor Fuel Economy: The engine's computer may inject too much fuel based on faulty sensor readings, causing you to visit the gas station more often.
- Rough Idle: An unstable or vibrating idle is a common symptom, as the computer struggles to maintain a proper air-fuel balance at rest.
- Hesitation or Lack of Power: When you accelerate, the engine might feel sluggish or hesitate because the computer isn't providing the right amount of fuel for the demand.
- Engine Stalling or Misfiring: In more severe cases, an incorrect air-to-fuel ratio can cause the engine to misfire, stall, or be difficult to start.
- Black Smoke from Exhaust: If the engine is running too rich (too much fuel), you might see black smoke coming from the tailpipe.
Check for Diagnostic Trouble Code (DTC) P0106
A very common trouble code associated with a failing MAP sensor is P0106. This code means the sensor's readings are outside of the expected range. While this often points to a bad sensor, it can also be caused by vacuum leaks, wiring issues, or even a dirty throttle body. It's a good idea to have the codes read with a scanner to help pinpoint the problem.
🎬 Watch this video to learn how to fix P0106 codes.Choosing the Right Aftermarket MAP Sensor
You do not need to buy a dealership part for a quality repair. Many aftermarket brands produce high-quality sensors, and some are even the original equipment manufacturer (OEM) for GM. Here’s a breakdown of available brands to help you choose.
Tier 1: Premium Aftermarket (OEM or Better Quality)
These brands are known for their quality and are often the original suppliers to automakers. They are your best bet for reliability and long-term performance.
- Bosch: Often the OEM for GM parts. Choosing Bosch is as close to a genuine factory part as you can get, ensuring excellent fit and performance.
- Delphi: Another top-tier OEM supplier for many GM components. Delphi parts are engineered to meet or exceed factory specifications.
- NGK (including NTK): NGK is a world-renowned brand, and its sensor division, NTK, is highly regarded for producing reliable and high-quality engine management parts.
Tier 2: Standard Aftermarket (Reliable Alternatives)
These brands offer a great balance of quality and value. They are trusted in the repair industry for providing reliable parts that perform correctly.
- Standard Ignition (Standard Motor Products): A well-respected aftermarket brand that has been around for a long time. They produce quality sensors that are a dependable choice for replacement. Avoid their budget "T-series" line if a premium repair is your goal.
- Walker Products: With a long history in fuel systems and engine sensors, Walker produces OE-equivalent parts that are 100% tested and designed to restore original performance.
Tier 3: Economy Brands
These brands, including Global Parts and True Tech, offer a functional repair at the lowest cost. They are suitable for budget-conscious repairs, but may not offer the same long-term durability or precise calibration as premium brands.
Is an OEM Part Better?
For a simple electronic sensor like the MAP, high-quality aftermarket parts from brands like Bosch or Delphi are often identical to the OEM part, sometimes even made in the same factory. You can get the same quality without paying the dealership price. The key is to stick with reputable aftermarket brands.
Cost of Replacing a MAP Sensor for a 2019-2021 Blazer
The cost is relatively low, especially if you do the work yourself. The part is easy to access and replace on most engines.
| Part or Service | Estimated Cost |
|---|---|
| New OEM GM MAP Sensor | $26 - $50 |
| New Aftermarket MAP Sensor | $39 - $69 |
| Shop Labor | $50 - $100 |
| Total DIY Cost (Aftermarket) | $39 - $69 |
| Total Shop Cost (Aftermarket) | $89 - $169 |
Frequently Asked Questions (FAQ)
Is it hard to replace a Blazer MAP sensor myself?
No, this is a very simple DIY job for most people. The MAP sensor is usually located directly on the intake manifold and held in place by a single bolt. You simply unplug the electrical connector, remove the bolt, and swap the old sensor for the new one. 🎬 Watch this step-by-step guide on replacing the sensor yourself. The entire job can take less than 15 minutes.
Are there any recalls for the Blazer MAP sensor?
No. As of early 2026, there are no specific recalls or technical service bulletins (TSBs) from Chevrolet or the NHTSA for MAP sensor issues on the 2019-2021 Blazer.
Can I just clean my MAP sensor?
While some sensors like the Mass Airflow (MAF) sensor can be cleaned, it is generally not recommended for MAP sensors. The internal components are delicate and sealed. Contaminants can clog the sensor's port, but the electronic failure itself cannot be fixed by cleaning. Given the low cost of a new part, replacement is the best option.
Could something else cause a MAP sensor code (P0106)?
Yes. A common cause for a false P0106 code on GM vehicles is a dirty electronic throttle body. Carbon buildup can restrict airflow at idle, causing the computer to see a pressure reading that doesn't match the throttle position. If you replace your sensor and the problem persists, inspecting and cleaning the throttle body 🎬 See how a dirty throttle body can trigger MAP codes. is a good next step.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12711664 55573248
The MAP sensor for the 2019-2021 Blazer is typically a 3 or 4-pin electronic sensor that mounts directly to the intake manifold. It provides a voltage signal to the ECM that varies with manifold pressure.
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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 MAP Sensor Failure in Your Blazer
- Symptoms of a Bad MAP Sensor
- Check for Diagnostic Trouble Code (DTC) P0106
- Choosing the Right Aftermarket MAP Sensor
- Tier 1: Premium Aftermarket (OEM or Better Quality)
- Tier 2: Standard Aftermarket (Reliable Alternatives)
- Tier 3: Economy Brands
- Is an OEM Part Better?
- Cost of Replacing a MAP Sensor for a 2019-2021 Blazer
- Frequently Asked Questions (FAQ)
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