Resetting the check engine light on a 1999 Ford Taurus can be done manually or with an OBD2 scanner. This guide walks you through both methods, explains when it’s safe to reset, and helps you avoid common mistakes. Always fix the underlying issue first to prevent the light from returning.
Key Takeaways
- Diagnose the problem first: Never reset the check engine light without identifying and fixing the root cause using an OBD2 scanner or professional help.
- Use an OBD2 scanner for accuracy: This tool reads trouble codes and safely resets the light, ensuring the issue is resolved.
- Manual reset method works but is less reliable: Disconnecting the battery can reset the light, but it may also erase important vehicle settings.
- Drive cycle completion is essential: After resetting, drive your Taurus through a complete drive cycle to allow the onboard computer to re-test systems.
- Check for persistent issues: If the light returns, there’s likely an unresolved problem requiring further diagnosis.
- Maintain your vehicle regularly: Prevent future check engine lights by keeping up with maintenance like spark plugs, oxygen sensors, and gas cap checks.
- Know when to seek professional help: Complex issues like catalytic converter failure or engine misfires should be handled by a certified mechanic.
How to Reset Check Engine Light 99 Ford Taurus
If you’re driving a 1999 Ford Taurus and the dreaded check engine light has popped up on your dashboard, you’re not alone. This amber warning light is designed to alert you to potential issues with your vehicle’s engine, emissions system, or onboard diagnostics. While it can be alarming, the good news is that in many cases, the light can be reset—especially after you’ve addressed the underlying problem.
But here’s the catch: simply turning off the light without fixing what caused it in the first place is like putting a bandage on a broken bone. The light will likely come back on, and you could be ignoring a serious issue that might lead to costly repairs down the road.
In this comprehensive guide, we’ll walk you through everything you need to know about how to reset the check engine light on a 1999 Ford Taurus. You’ll learn two reliable methods—using an OBD2 scanner and manually disconnecting the battery—plus essential tips for diagnosing the problem, avoiding common mistakes, and ensuring your Taurus runs smoothly after the reset.
Whether you’re a DIY enthusiast or just trying to save a trip to the mechanic, this guide will give you the confidence and know-how to handle the check engine light like a pro.
Understanding the Check Engine Light
Visual guide about How to Reset Check Engine Light 99 Ford Taurus
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Before we dive into the reset process, it’s important to understand what the check engine light actually means. On a 1999 Ford Taurus, this light is part of the vehicle’s On-Board Diagnostics II (OBD2) system, which monitors engine performance, emissions, and various sensors.
When a problem is detected—such as a faulty oxygen sensor, loose gas cap, or misfiring spark plug—the system stores a diagnostic trouble code (DTC) and triggers the check engine light. The light can appear as either a steady glow or a flashing signal. A steady light usually indicates a minor issue, while a flashing light suggests a more serious problem that could damage the catalytic converter if ignored.
It’s crucial to note that the check engine light doesn’t tell you exactly what’s wrong—it only signals that something needs attention. That’s why diagnosing the issue is the first and most important step before attempting any reset.
Step 1: Diagnose the Problem
You should never reset the check engine light without first figuring out why it came on. Resetting it prematurely can mask a serious issue and lead to further damage or safety risks.
Use an OBD2 Scanner
The most effective way to diagnose the problem is by using an OBD2 scanner. These devices plug into your vehicle’s diagnostic port—usually located under the dashboard on the driver’s side—and read the trouble codes stored in the computer.
Here’s how to use one:
- Locate the OBD2 port: In the 1999 Ford Taurus, it’s typically found beneath the steering column, near the fuse panel. It’s a 16-pin connector that looks like a trapezoid.
- Plug in the scanner: Turn the ignition to the “ON” position (but don’t start the engine), then connect the scanner to the port.
- Read the codes: Follow the scanner’s instructions to retrieve the trouble codes. Common codes for the 1999 Taurus include P0420 (catalytic converter efficiency), P0171 (system too lean), and P0300 (random misfire).
- Interpret the codes: Use the scanner’s manual or an online database to understand what each code means. This will help you identify the root cause.
Visit a Repair Shop or Auto Parts Store
If you don’t own an OBD2 scanner, many auto parts stores (like AutoZone, O’Reilly, or Advance Auto Parts) offer free code reading services. Simply drive your Taurus to the store, and a technician will plug in a scanner and tell you the trouble codes.
Once you have the codes, you can research the issue online or consult a mechanic for advice. Some common fixes for the 1999 Ford Taurus include:
- Tightening or replacing the gas cap
- Replacing a faulty oxygen sensor
- Changing spark plugs or ignition coils
- Cleaning the mass airflow (MAF) sensor
- Repairing vacuum leaks
Address the Underlying Issue
After diagnosing the problem, take the necessary steps to fix it. For example, if the code indicates a loose gas cap, simply tighten it and see if the light turns off after a few drives. If it’s a more complex issue like a failing catalytic converter, you may need professional assistance.
Only after the issue is resolved should you proceed to reset the check engine light.
Step 2: Choose a Reset Method
Once the problem is fixed, you can reset the check engine light using one of two methods: an OBD2 scanner or manual battery disconnection. Each has its pros and cons, so let’s explore both.
Method 1: Using an OBD2 Scanner (Recommended)
This is the safest and most reliable way to reset the check engine light. It ensures the vehicle’s computer recognizes that the issue has been resolved and clears the stored codes.
Here’s how to do it:
- Ensure the engine is off: Turn the ignition to the “OFF” position.
- Plug in the scanner: Connect the OBD2 scanner to the diagnostic port under the dashboard.
- Turn the ignition to “ON”: Do not start the engine—just turn the key to the “ON” position so the scanner can communicate with the computer.
- Navigate the scanner menu: Use the scanner’s interface to select “Clear Codes” or “Reset Check Engine Light.” This option is usually found under “Diagnostics” or “Tools.”
- Confirm the reset: Follow the prompts to confirm. The scanner will send a signal to the vehicle’s computer to erase the trouble codes and turn off the check engine light.
- Turn off the ignition and disconnect the scanner: Wait a few seconds, then remove the scanner and turn the key back to “OFF.”
After resetting, start your Taurus and check the dashboard. The check engine light should be off. If it remains on or comes back shortly after, the issue may not be fully resolved.
Method 2: Manual Reset by Disconnecting the Battery
If you don’t have access to an OBD2 scanner, you can reset the check engine light by disconnecting the car battery. This method forces the vehicle’s computer to reset by cutting power to its memory.
However, this approach has drawbacks. It may erase other settings like radio presets, clock time, and adaptive transmission learning. It also doesn’t guarantee that the computer will fully clear all codes, especially if the issue persists.
Here’s how to do it safely:
- Turn off the engine and remove the key: Make sure the vehicle is completely off.
- Locate the battery: Open the hood and find the battery. In the 1999 Ford Taurus, it’s usually on the driver’s side.
- Disconnect the negative terminal: Use a wrench to loosen the nut on the negative (black) battery cable. Carefully remove the cable and tuck it away from the battery terminal to prevent accidental contact.
- Wait 15–30 minutes: This allows the vehicle’s computer to fully discharge and reset. Some experts recommend waiting up to an hour for a complete reset.
- Reconnect the battery: Reattach the negative cable and tighten the nut securely.
- Start the vehicle: Turn the ignition to “ON” and then start the engine. Check the dashboard to see if the check engine light is off.
If the light is off, great! But remember, this method doesn’t confirm that the original problem is fixed—it only resets the light. If the issue persists, the light will likely return.
Step 3: Complete a Drive Cycle
After resetting the check engine light, your 1999 Ford Taurus needs to complete a “drive cycle” so the onboard computer can re-test all monitored systems. This process ensures that the vehicle is operating within normal parameters and that no new issues have arisen.
A drive cycle typically involves a combination of city and highway driving under various conditions. Here’s a general drive cycle for the 1999 Taurus:
- Start with a cold engine: Let the car sit overnight so the engine is cold.
- Drive at varying speeds: Begin with city driving—accelerate to 30–40 mph, then decelerate and stop at traffic lights. Repeat this for about 10–15 minutes.
- Switch to highway driving: Get on the highway and drive at a steady speed of 55–65 mph for 10–15 minutes.
- Decelerate gradually: Slow down without braking hard, allowing the vehicle to coast.
- Repeat if necessary: Some systems may require multiple drive cycles to complete testing.
During this process, the computer will monitor systems like the oxygen sensors, catalytic converter, and evaporative emissions. If everything checks out, the readiness monitors will show as “complete” when scanned again.
Troubleshooting Common Issues
Even after resetting the check engine light, you might encounter problems. Here are some common issues and how to address them:
The Light Comes Back On
If the check engine light returns shortly after resetting, it means the underlying issue wasn’t fully resolved. Possible causes include:
- A recurring fault (e.g., intermittent misfire)
- A partially fixed problem (e.g., a dirty MAF sensor that needs cleaning, not just resetting)
- A new issue that developed after the reset
Solution: Re-scan the vehicle with an OBD2 scanner to retrieve new or recurring codes. Address the root cause before resetting again.
The Light Won’t Turn Off
If the light remains on after a reset, the problem may be more serious. This could indicate:
- A persistent engine misfire
- Catalytic converter failure
- Faulty engine sensors (e.g., crankshaft position sensor)
Solution: Consult a certified mechanic for a thorough diagnosis. Some issues require specialized tools or replacement parts.
Battery Disconnection Caused Other Problems
After disconnecting the battery, you might notice:
- Radio presets are gone
- Clock needs resetting
- Transmission shifts roughly
Solution: Reprogram the radio and clock. For transmission issues, drive the vehicle normally for a few days to allow the computer to relearn shift patterns.
Preventing Future Check Engine Lights
The best way to deal with the check engine light is to prevent it from coming on in the first place. Regular maintenance is key to keeping your 1999 Ford Taurus running smoothly.
Here are some preventive tips:
- Check the gas cap: A loose or damaged gas cap is one of the most common causes of the check engine light. Make sure it’s tight and the seal is intact.
- Replace spark plugs and wires: Worn spark plugs can cause misfires. Replace them every 30,000–60,000 miles.
- Inspect oxygen sensors: These sensors monitor exhaust gases and can degrade over time. Replace them if you notice poor fuel economy or rough idling.
- Clean the MAF sensor: Use a specialized cleaner to remove dirt and debris from the mass airflow sensor.
- Use quality fuel: Low-quality gasoline can lead to carbon buildup and engine knocking.
- Follow the maintenance schedule: Refer to your owner’s manual for recommended service intervals.
When to See a Mechanic
While many check engine light issues can be resolved at home, some problems require professional attention. Seek a mechanic if:
- The light is flashing (indicating a severe misfire)
- You notice symptoms like rough idling, loss of power, or strange noises
- The same code keeps returning after repairs
- You’re unsure how to interpret or fix the trouble code
A certified technician has the tools and expertise to diagnose and repair complex issues, ensuring your Taurus stays safe and reliable.
Conclusion
Resetting the check engine light on a 1999 Ford Taurus is a straightforward process—but only after you’ve properly diagnosed and fixed the underlying issue. Whether you use an OBD2 scanner or disconnect the battery, the key is to ensure the problem is resolved before clearing the codes.
Remember, the check engine light is your vehicle’s way of saying, “Hey, something’s not right.” Ignoring it can lead to bigger problems, higher repair costs, and even safety hazards. By following the steps in this guide, you can confidently reset the light, complete a drive cycle, and keep your Taurus running smoothly for years to come.
Stay proactive with maintenance, use the right tools, and don’t hesitate to seek professional help when needed. Your 1999 Ford Taurus has served you well—now it’s time to give it the care it deserves.