Dodge Grand Caravan Vehicle Speed Sensor Guide: 1987-1994
Fix your erratic speedometer and shifting problems by understanding the vehicle speed sensor in your first-generation Grand Caravan.
- A bad vehicle speed sensor is a very common cause of erratic speedometers and shifting problems in 1987-1994 Grand Caravans with the A604/41TE automatic transmission.
- Symptoms include a dead or jumping speedometer, harsh shifting, getting stuck in gear ('limp mode'), and a non-working cruise control.
- This is an easy and inexpensive DIY repair that requires basic tools; the sensors are located on the outside of the transmission.
- It is highly recommended to replace both the input and output speed sensors at the same time, as they are the same part and tend to fail around the same time.
Is Your Speedometer Acting Up?
If you own a first-generation Dodge Grand Caravan, you might experience issues with the speedometer or transmission shifting. These problems are often linked to a failing Vehicle Speed Sensor (VSS). This sensor is a known weak point on the popular A604 electronic automatic transmission used in these minivans. When it fails, it can make your van feel unpredictable and unsafe.
Limp Mode is a Common Symptom
A complete failure of the speed sensor can force the transmission into "limp mode." This is a safety feature where the transmission stays in second gear to prevent further damage. You will notice very high RPMs at moderate speeds and the van will 🎬 Watch: How to troubleshoot and fix transmission limp mode have trouble accelerating from a stop.
Symptoms of a Bad Vehicle Speed Sensor
A failing VSS can cause several noticeable problems. Here’s what to look for:
- Erratic or Dead Speedometer: The needle may jump around wildly, read incorrectly, or not move at all.
- Harsh or Failed Shifting: The transmission may slam into gear, hesitate, or refuse to shift out of a low gear.
- Cruise Control Not Working: The cruise control system relies on the VSS signal to maintain speed. If the signal is gone, it won't engage.
- Check Engine Light: A faulty speed sensor will often trigger a Check Engine Light. Common codes include P0500 (Vehicle Speed Sensor Malfunction) and others related to the transmission output speed sensor circuit.
Choosing the Right Aftermarket Sensor
You don't need to buy an expensive OEM part from the dealer. Several reputable aftermarket brands offer quality replacements. Aftermarket parts for this van are widely available and offer a good balance of price and quality.
Aftermarket Brand Tiers
| Brand Tier | Brands | Why? |
|---|---|---|
| Better (OE Quality) | Delphi, Standard Ignition (SMP) | Both are well-known OE suppliers. They manufacture parts to high standards, ensuring proper fit and a reliable signal. Delphi emphasizes testing to OE standards for accurate readings. Standard Ignition controls its manufacturing process from start to finish. |
| Good (Quality Aftermarket) | Walker Products, True Tech | Walker Products positions itself as meeting or exceeding OEM specifications and is a long-standing company in engine management parts. True Tech is a solid standard replacement option. |
| Economy | URO Parts, Skyward | URO Parts is known for being a budget-friendly alternative, often for European cars, but they make parts for domestic vehicles too. These brands are a viable choice if the price is your main concern, but long-term durability may not match higher-tier brands. |
Pro Tip: Replace Both Sensors
Your Grand Caravan's A604 transmission has both an input and an output speed sensor. They are identical parts and often fail around the same time. Since they are relatively inexpensive and located near each other, it's a good idea to replace them as a pair to avoid 🎬 See this walkthrough for replacing input and output sensors future problems.
Frequently Asked Questions (FAQ)
Where is the vehicle speed sensor located on a 1987-1994 Grand Caravan?
For the common 4-speed electronic automatic (A604/41TE), you will find two sensors. The output speed sensor is typically located on the side of the transmission, sometimes under the battery tray area. The input sensor is nearby, often just to the right of the transmission dipstick and below the cooler lines.
Is this a difficult part to replace myself?
No, this is a very DIY-friendly job. The sensors are held in by a single bolt and have a simple electrical connector. Access can be a bit tight, but it only requires basic hand tools. You'll need a ratchet and a 1-inch socket. The sensors are plastic, so they don't require a lot of force to remove or install.
What is the difference between an input and output speed sensor?
The input sensor measures the speed of the transmission's input shaft (how fast it's being spun by the engine). The output sensor measures the output shaft's speed (how fast the wheels are turning). The computer compares these two signals to detect clutch slippage and control shifting. The output sensor is the one that feeds the speedometer.
My speedometer is stuck. Could it be something else?
Yes. While the VSS is the most likely cause, the problem could also be a faulty speedometer gauge itself or an electrical issue like a bad ground or a problem with the instrument cluster's circuit board. On some models, you can perform a gauge cluster self-test by holding down the trip reset button while turning the key on, which will sweep all the needles.
🎬 Watch: How to perform a speedometer reset and gauge testHelpful Videos
Technical Specifications
OEM Part Numbers: 4800879 4800878 4439059 4671019
For models with the A604 (41TE) 4-speed automatic transmission, there are two sensors: an input and an output. They are often the same part number. The sensor is a magnetic pickup that reads the rotational speed of a shaft inside the transmission. It typically has a 2-pin electrical connector.
We Have This Part in Stock
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.
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