DTC P0107 – How To Test your LS1 MAP Sensor

Trouble with your Manifold Absolute Pressure (MAP) sensor can often lead to headaches in your LS1 swap. The OBDII DTC Trouble Code P0107 refers to your MAP sensor sending the Powertrain Control Module (PCM) too low of a signal circuit.

The GM LS1 Manifold Absolute Pressure sensor is part number 12614970 and it’s connected by way of a three pin weatherproof connector in the back of your intake manifold. For more information, check our LS1 Sensor swap guide or our LS1 part number guide.

The signal circuit reference from this sensor helps your PCM control and manage your LS1 fuel and ignition trims. Because the signal sent is too low and out of range for your GM PCM, the car will either be stuck in limp mode or run very very sluggishly.

Today we’ll be checking the manifold absolute pressure (MAP) sensor in a LS1 swapped S14 Nissan 240SX and showing you How To Test your LS1 MAP Sensor. To perform this test you will need a multimeter and some luck to remove the MAP sensor and connector while in the car.

First let’s locate the MAP sensor in your LS1 intake manifold. It’s mounted in the rear of the intake manifold and will be near your brake booster adjacent the firewall.

Now unplug the MAP sensor and reference the three wires on the connector as you face it. You can also look for markings such as 1 or 3 to indicate which way you are looking at the pins.

Shown above is the stock LS1 MAP connector next to a Bosch style standalone three bar  map sensor. Disregard the Bosch unit for now, we’ll be wiring that sensor in at a later time.

To begin testing, reference the chart below for the LS1 MAP sensor wiring pinout and diagram.

You will be using your multimeter to test these three pins in our How To Test your LS1 MAP Sensor. Put the key in the ignition and turn it to the “ON” position but do not start the vehicle.

Put the black lead on the negative side of your battery and check the power pin on your LS1 MAP sensor connector. The power wire for your LS1 MAP sensor is PIN 3, highlighted in the image below.

This wire is a green wire with a yellow stripe and you should see 5 volts of switched power here at this wire with the key at the “ON” position. The next wire to check will be PIN 1 or the orange wire with black stripe, providing the ground or low reference signal to power your MAP sensor.

If you do not have power or ground here at these two wires, you’ve got other issues that outweigh your P0107 OBDII Trouble Code. The GM MAP Sensor can stop receiving power if there’s a short in an existing sensor elsewhere on your LS1 block. You can also have a friend slowly unplug sensors one at a time until your MAP sensor shows power again.

If this occurs, the last sensor you unplugged is the one with the short in it. If you do have power and ground at this sensor, that means that your sensor may have gone bad.

The last step in our How To Test your LS1 MAP Sensor article is to remove the entire MAP sensor all together. Once the MAP sensor is removed, reconnect the MAP sensor connector and backprobe the green wire or PIN 2. Now with the key to the “ON” position but engine off, gently suck on the opening of the MAP sensor to create a vacuum.

You should see the values on the green wire or signal wire fluctuate slowly. Without vacuum you should see 4.4-4.5 volts at this middle wire. As you slowly add vacuum, you should see this voltage decrease accordingly.

If this wire does not respond correctly, your LS1 MAP sensor has failed and must be replaced. That does it for our How To Test your LS1 MAP Sensor article, replace your MAP sensor and clear your OBDII codes to continue.

Please let us know if you have any questions or comments regarding our How To.