Jeep Grand Cherokee Speed Sensor Guide for 1999-2005 Models
Fix your Grand Cherokee's erratic shifting and jumping speedometer by understanding and choosing the right replacement sensor.
- Symptoms of failure include erratic shifting, a jumping speedometer, and a Check Engine Light with code P0720.
- Verify your engine (4.0L or 4.7L) to know if you need one or two sensors and their exact location on the driver's side of the transmission.
- This is a very easy DIY replacement that can be done in under an hour with basic tools.
- Always inspect the wiring and connector for damage before replacing the sensor, as this can cause identical symptoms.
Understanding Speed Sensors in Your WJ Grand Cherokee
If your 1999-2005 Grand Cherokee (WJ) is shifting hard, the speedometer is acting erratically, or it feels stuck in a low gear, a failing transmission speed sensor is a very common cause. This part is essential for proper transmission function, and when it fails, it creates noticeable drivability problems. Fortunately, it's an inexpensive and straightforward part to replace for most DIY mechanics.
It's important to know that your Jeep has several "speed sensors." The ones that cause shifting problems are located on the transmission. There are also ABS wheel speed sensors at each wheel, which are part of the anti-lock brake system. This guide focuses on the transmission speed sensors.
- 4.0L I6 Engine (42RE Transmission): These models have a single output speed sensor located on the driver's side, at the rear of the transmission's overdrive section.
- 4.7L V8 Engine (45RFE/545RFE Transmission): These models have two sensors on the driver's side of the transmission case: an input sensor and an output sensor. The output sensor is the rearmost of the two and is the one that provides the vehicle speed signal. In many cases, both the input and output sensors are the same part number. 🎬 See how to replace both sensors on the 45RFE transmission.
Check the Connector First!
Before replacing the sensor, always inspect the wiring and the plastic connector. On these Jeeps, the wiring harness leading to the sensor can get damaged or corroded from road debris and heat. A bad connection can cause the exact same symptoms as a failed sensor, and a visual check could save you from replacing a perfectly good part.
Choosing the Right Aftermarket Speed Sensor
When it comes to electronic parts like speed sensors, quality matters. While OEM Mopar sensors are the benchmark, a quality aftermarket part can provide reliable performance for a lower price. For a vehicle of this age, a well-regarded aftermarket sensor is a practical choice. Some owners and mechanics report that Chrysler vehicles can be sensitive to aftermarket electronic parts, so it's best to stick with known brands rather than the cheapest option available. 🎬 Learn why some mechanics recommend avoiding aftermarket sensors. Since the "Replacement" brand is a standard-tier part, it should meet the basic requirements for function, but don't expect the same longevity or precise calibration as a premium or OEM part.
Cost Comparison: 1999-2005 Grand Cherokee Speed Sensor
| Part Type | Estimated Cost |
|---|---|
| New OEM (Mopar) | $35 - $60 |
| New Aftermarket (Replacement Brand) | $22 - $32 |
| Shop Labor | $75 - $150 |
Frequently Asked Questions (FAQ)
Where is the speed sensor on my 1999-2005 Grand Cherokee?
It's on the driver's side of the transmission. For 4.0L engines, it's a single sensor at the very back. For 4.7L V8 engines, there are two sensors; the output speed sensor is the one further back.
Can I replace the speed sensor myself?
Yes, this is a very DIY-friendly job. It typically involves raising the vehicle safely, unplugging one electrical connector, and removing a single bolt (usually 8mm). The entire process can often be done in under an hour with basic tools.
What are the symptoms of a bad speed sensor on a WJ Grand Cherokee?
The most common symptoms are an erratic or non-working speedometer, harsh or delayed transmission shifting, and the transmission getting stuck in "limp mode" (usually first or second gear). The Check Engine Light will also likely be on, with code P0720 being the most common.
🎬 Watch this video to see common P0720 code symptoms.Are there any recalls for the speed sensor on these Jeeps?
No, there have been no specific recalls issued by the NHTSA for the transmission speed sensors on the 1999-2005 Jeep Grand Cherokee. There was a recall for some 2005 models related to the torque converter, but not the speed sensor itself.
Helpful Videos
![99 - 04 Jeep Grand Cherokee: how to replace transmission speed sensors [45RFE transmission]](https://img.youtube.com/vi/TWUqx0FrLtM/mqdefault.jpg)
Technical Specifications
OEM Part Numbers: 4800879 4799061AB
2-pin oval connector, magnetic pickup sensor. Located on the driver's side of the transmission case.
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.
- Jeep Grand Cherokee: