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Jeep Grand Cherokee 1999-2004: How to Replace Crankshaft Position Sensor

Does your Jeep Grand Cherokee's timing feel off? Your crankshaft position sensor may need to be replaced. Read on to learn how you can replace it yourself.

By Bassem Girgis - October 14, 2015

This article applies to the Jeep Grand Cherokee WJ (1999-2004).

The crankshaft position sensor is a small electronic sensor in your Jeep Grand Cherokee, and it is designed to capture reading on the position of your crankshaft. The readings then goes to the computer in your Jeep, and using the information, the car can idle smoothly. If the crankshaft position sensor malfunctions in your Jeep, you will be able to drive the car until you turn it off, in which case you may not be able to start it back up. If the car doesn't go in limp mode, your gas mileage will suffer tremendously, so replacing it as soon as possible is very important. Read on to learn how you can replace the crankshaft position sensor yourself.

Figure 1. Crankshaft position sensor.

Materials Needed

  • 3/8 ratchet with extension and swivel head
  • New crankshaft position sensor
  • Towel

Step 1 – Disconnect the battery

Disconnect the negative battery terminal (black). Then wrap it in a towel to avoid it touching with any metal.

Figure 2. Disconnect battery (black terminal).

Step 2 – Remove crankshaft position sensor

Locate the crankshaft position sensor. It's located on top of the transmission's bell housing, under the firewall. This is a very tight squeeze, so you will need to use your ratchet with plenty of extension to reach it. The sensor has a wire connector connected to it. The connector is under the hood, which is connected with a long wire that is connected to the sensor itself. Unplug the connector under the hood, and to get an exact location on the sensor, follow the wire down.

From under the vehicle, use your ratchet with an extension and swivel head to unbolt the two bolts holding the sensor to the transmission's bell housing.

  • Figure 3. Crankshaft position sensor diagram.
  • Figure 4. Crankshaft position sensor's connector under hood.

Step 3 – Install new sensor

To align the new crankshaft position sensor's bolts, you will need to squeeze your hand through from the top, where the connector and wire go down to the sensor. If your arm doesn't fit in the tight squeeze, put some grease in the end of your swivel head, and use it to hold the bolt until you align it as well as tighten it properly. Once you've tightened the bolts, start your car to test.

  • Figure 5. Push your hand through.
  • Figure 6. Align the bolts.

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