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How To Test a Chevy Silverado MAP Sensor

The pressure sensor in your Chevy Silverado is mounted to the intake manifold. This sensor is also known as the Silverado MAP Sensor, or manifold absolute pressure sensor. This unit is meant to read the barometric pressure of the air entering your engine. Your Chevy Powertrain Control Module uses this data to deliver the right amount of fuel and spark to your engine.

When your Silverado MAP Sensor starts to go bad, you are going to have some issues with your engine to say the least. Your idle may be rough but more than likely your Silverado will run rich or use too much fuel. If you don’t correct this issue, the excessive hydrocarbons can elevate your exhaust gas temperature to the point of your catalytic converter failing.

If you think your Silverado MAP sensor is going bad, this How To Guide can help you test it. Today I’ll be showing you how to test the manifold absolute pressure sensor in a 2007 Chevy Silverado with a 5.3 liter engine in it. In order to complete this test however you will need to use a digital multimeter to read the voltage at the engine harness.

The three wire MAP sensor in your vehicle is mounted to the top of the intake manifold. It uses a ribbed grommet to help secure and seal the air pressure, and to prevent your engine from running lean.

Symptoms of a failed Silverado MAP Sensor

When this pressure sensor goes bad your 5.3 liter engine will have several problems or symptoms that can cause driveability issues. Here’s some of the more common symptoms from a bad MAP sensor.

When your check engine light turns on in your Silverado instrument cluster, you’ll need an OBDII scan tool to retrieve the stored codes. To begin this DIY tutorial, we’ll begin by checking the Silverado MAP Sensor for power.

Checking the Silverado MAP Sensor for Power

Open your Silverado hood and locate the MAP sensor, which is connected to the intake manifold. Unplug this MAP harness and the wire you’ll be testing first is PIN A on the ENGINE harness side. Make sure your key is inserted and turned to the “ON” position. There should be around 5 volts of DC power here at this wire.

If you have power here, great the next wire to check is the low reference ground wire. This is the wire that connects to PIN C, and if you’ve got a ground here then great your Silverado MAP Sensor is getting what it needs to operate.

Chances are now that your MAP sensor OBDII trouble code is still around, even after you’ve cleared it. If you know that your pressure sensor is getting power and ground but the trouble code is still present, you need to test the Silverado MAP Sensor signal.

This is done by reconnecting the MAP sensor connector, and using a vacuum pump to the port of the pressure sensor. You can purchase one of these at your local auto store, or simply pick up a Mighty Vac pump.

Reconnect the Silverado MAP Sensor harness and the wire you will need to read is the one that’s connected to PIN B. This wire is your signal wire, and you’ll be using the hand pump to deliver vacuum to the MAP sensor inlet.

With the key turned to the “ON” position you should see between 4.5-4.8 volts of DC signal at this wire. Remember that this part of the test may vary but as long as you are close to these readings your Silverado MAP Sensor is okay. Now apply 5 in. Hg of vacuum to the MAP inlet, at this reading you should have between 4.1 and 3.9 volts of DC signal. Increase the vacuum to 10 in. Hg and at this reading you should have between 3.0 and 2.8 volts.

If your Silverado MAP Sensor does not respond with this range of voltage, it’s time for a pressure sensor replacement. Have any questions about our How To test a Silverado MAP Sensor guide? Leave them for us below and let us know!

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