How to Reset the Check Engine Light on Cars

by Contributing Writer; Updated June 12, 2017

There are two methods for resetting the "service engine soon" light on a Nissan car. One method, which is the most convenient, is to use a code scanner, which you can purchase at any auto parts store. The code scanner will display the codes automatically and has an accompanying code sheet. There is also a manual way to display the codes and reset the computer -- you need to access a code sheet the decipher the codes. The trouble codes must be repaired prior to resetting the computer, because the light will just come back on as long as it sees the failure.

Under The Hood:

 How to Reset the Check Engine Light on a Mercedes

Insert the key in the ignition switch and turn it without starting the car. Pay attention to the display on the instrument cluster between the speedometer and the tachometer.

Press the lower left button on the left side of the steering wheel. There are four buttons on the left side of the steering wheel. After pushing the button, the display will reveal why the check engine light is lit. Usually it indicates that the car is due for service. Push the lower left button on the steering wheel again and the vehicle mileage will show on the display.

Press the lower right button on the left side of the steering wheel. This will again show the reason why the "check engine" light is on.

Locate the reset button on the left side of the instrument cluster. Press the reset button and hold it until the display reads "To reset: Press reset button for 3 seconds."

Push the reset button again and hold the button in until the display indicates that the system has been reset. The display will also inform you of the next service date according to mileage.

Items you will need

  • Ignition key

 How to Reset the Service Engine Soon Light on a Nissan Altima

Pulling The Codes With a Code Scanner

Plug the code scanner's plug in the on board diagnostics port under the dash, to the left of the steering column. Turn the key to the "On" position, without starting the car.

Press the "Read" key on the scanner, and it will begin to display all the codes. Make a note of the codes for cross-reference. All codes are formatted, so they display a letter followed by four numbers.

Cross-reference the codes with the code sheet. This can be found on-line or at an auto parts store. Repair all faults represented by the codes.

Turn the ignition key to the "On" position, without starting the car. Press the "Erase" key to erase the codes and reset the computer.

Pulling The Codes Without a Scanner

Turn the ignition key to the "On" position, without starting the engine. Wait three seconds. Depress and release the gas pedal five times in five seconds, then let the pedal up. Count seven seconds and then depress the gas pedal and hold it down for 10 seconds. As soon as the service engine soon light starts flashing trouble codes, let the pedal up.

Make a note of all the codes by counting the flashes. For example, if the light will flash four times in a row and pause for a second and begin flashing again, the first four flashes stand for the number 4; it will then proceed to the next number.

Cross-reference these number codes with a code sheet. Repair all the faults before resetting the computer.

Reset the computer and turn the service engine soon light off by repeating the first process completely, with one exception: When the pedal is lifted after pressing the pedal down for 10 seconds and the codes are flashing, depress the pedal again for an additional 10 seconds and the computer will reset.

Items you will need

  • Diagnostic scanner

 How to Reset the Check Engine Light of the Chrysler

Let the light reset itself. When the engine trouble has been fixed, a Chrysler engine resets the "Check Engine" light automatically after 40 successful runs. If it doesn't reset, the problem likely still exists.

Force the computer into "Successful Run" mode. Start the Chrysler and drive forward a few feet, then put it in reverse and go backward a few feet. Do this three times and shut the engine off. Crank it again to see if the light has been cleared.

Disconnect the battery for several minutes. This resets everything in the vehicle, including the clock and radio settings. Reapply the radio settings and adjust the time when the battery is reconnected.

Use a diagnostic scanner to clear the codes. Connect the scanner to the test port, also called the ALDL (Assembly Line Diagnostic Link) usually located under the dash (see Resources section). Turn the engine "On" and follow the prompts on the scanner to pull the engine codes. Select the option to clear them.

Items you will need

  • Diagnostic scanner

 How to Reset the Service Engine Soon Light on My Nissan

Open the hood and loosen the retaining nut on the negative battery cable clamp using a socket wrench.

Slide the cable clamp off of the negative battery terminal.

Wait 5 minutes and reconnect the battery cable and then tighten the retaining nut with the socket wrench.

Turn the ignition on and wait for the "service engine soon" light to blink and shut off. This will reset the light on your dash.

Items you will need

  • Socket wrench

  • 10mm Socket

 How to Reset a Service Engine Light in a Mitsubishi Montero

Resetting the Light by Disconnecting the Battery

Verify you have the correct anti-theft code for your radio. All Mitisubishi factory radios have an anti-theft lockout; if the battery is disconnected, the radio will not work until the code is entered.

Turn the engine off and open the hood to access the battery.

Use a wrench to loosen the nut around the negative battery cable first, and then slip the cable away from the terminal.

Loosen the nut around the positive battery cable. Pull the cable away from the terminal.

Leave the battery disconnected for five to 10 minutes and then reattach the positive battery cable and tighten the nut.

Reattach the negative battery cable and tighten the nut. Start the engine, verify the service engine light is off. Your radio should say "Code."

Enter your radio code using the corresponding numbers on the radio preset buttons. When you have entered it, press the "CD" button. The radio will return to normal operation. If you have an aftermarket radio, this will not be necessary.

Resetting the Light with an OBD-II Code Scanner

Turn your ignition to the "Acc" or "On" setting, without starting the engine.

Attach the OBD-II scanner port to the diagnostic port on the Montero. The diagnostic port is on the driver's-side, beneath the steering wheel.

Wait for the scanner to read the system and then press "Clear" or "Reset" to reset the service engine light.

Items you will need

  • Wrench

  • OBD-II scan tool (optional)

 How to Reset the Check Engine on a Hyundai Tucson

Open the driver's door and locate the lever to release the engine hood latch. Pull the latch until you hear the hood release.

Open the hood and ensure that it is properly supported. While most models have self-sustaining hoods, some may still have a rod that you must prop up in order to keep it from falling.

Locate the battery in the engine compartment. Look for the negative terminal on the battery by the "-" sign next to it.

Using a 1/4 or 3/8 ratchet, remove the bolt keeping the negative terminal on and completely disconnect it. Let the battery sit unplugged for at least 5 minutes.

Reconnect the battery, ensuring not to screw the bolt back on too tightly. Start up your car and verify the check engine light is now off. If the light remains on, or turns back on at any point, then a problem still exists with the car and should be inspected by a certified technician.

Items you will need

  • 1/4 or 3/8 socket wrench with sockets.

 How to Reset the Service Engine Light on the Mitsubishi Eclipse

Pre-1996

Turn off the ignition key. Disconnect the battery cables from the battery located on the front passenger's side of the engine compartment. Loosen the 10 mm battery cable end bolt with a 10 mm wrench and twist while pulling the cable from the terminal. Repeat for the positive cable end.

Touch the cable ends together and turn the ignition key to the "On" position. This will drain the capacitors that store the power for the memory in the on-board computer. Leave the battery disconnected for 15 minutes to ensure the memory is reset.

Reconnect the battery cables beginning with the positive cable end and tighten the cable end bolts securely. Test-drive the car in both city and highway conditions to allow the on-board computer to relearn the fuel trim and idle speed.

Post-1996

Connect a scan tool to the diagnostic port located under the driver's side of the dash near the steering column. Turn the ignition key to the "On" position.

Read the codes and descriptions by selecting "OBD-II Diagnostics" from the menu on the scan tool display then select "Read Codes" from the diagnostic menu. It may be useful to write down the existing codes and descriptions for future diagnostics if the repair proves unsuccessful.

Erase the codes by selecting "Erase" or "Clear Codes" from the menu. Select "Yes" when the warning message is displayed asking if you are sure you want to erase the codes. Test-drive the car in both city and highway driving conditions to allow the computer to relearn fuel trims and run its automatic emissions control checks.

Items you will need

  • Wrench set

  • Scan tool

 How to Reset the Engine Light in a Jeep Commander

Open the driver's side door of the Jeep Commander and then locate the Diagnostic Link Connector (DLC) below the dash. This trapezoidal-shaped outlet may or may not have a protective plug covering it on the Commander. If a plug is present, pull it off by hand.

Plug the OBD II code reader into the DLC and then turn the ignition key to the key-on/engine-off position. This position is two forward clicks in the ignition that will power the Commander's electrical components without starting the engine. This will also provide portable power to the OBD II code reader.

Follow the instructions on the screen/menu of the code reader. There are many brands and types of code readers, but most employ a main menu with and up and down scroll button and an "Enter" or "Send" button.

Scroll to the "Read codes" option on the scanner and press the Enter button.

Write the code(s) down on a piece of paper for future reference. This is in the event the code(s) present on the Commander have been previously diagnosed and corrected by the repairs that caused the MIL to illuminate. In the event the MIL re-illuminates, refer to the paper and code as a reference.

Scroll back to the main menu on the OBD II code reader and select the"Erase codes" option. The reader will most likely ask if you're sure you want to perform this step. Choose "Yes." A "Command sent" message will appear on the code reader, but do not remove the plug from the DLC until the main menu reappears.

Start the engine to the Jeep Commander and inspect the instrument panel to ensure the MIL is out.

Items you will need

  • OBD II code reader/code eraser

 How to Reset the Service Engine Soon Light on a Grand Am

Turn the ignition switch on without starting the engine.

Press the "Options" button on the instrument panel until the service light is displayed.

Press the "Set/Reset" button to open the reset confirmation screen.

Turn the ignition switch off. If the message comes back on when the car is turned back on, repeat the process.

 How To Reset the Service Engine Soon Light in a 1999 Buick Century

Put the key into the ignition and turn it to "Run." Don't start the engine.

Press down slowly and fully on the gas pedal, then release it. Do this three times in five seconds.

Watch for the "Service Engine Soon" light to start blinking. This indicates that the system is resetting itself. Turn the ignition to "Off" and wait one minute.

Start the Century's engine. The Service Engine Soon light will flash for a moment, then turn off. If it doesn't do this, repeat the process.

Items you will need

  • Ignition key

 How Do You Reset a Check Engine Light on a Honda Element?

Resetting the Light

Attach the code scanner to the hookup located underneath the dashboard on the driver's side of the Element. Start the vehicle and turn on the scanner and let it read the error code. Write down the error code.

Use the reset function on the scanner to tell the car's computer to turn of the light. Unplug the scanner and turn off the engine. Wait one to two minutes and then start the car again. The light should remain off.

Turn on the engine of your Honda Element once again. If the light comes back on, this signifies a critical error and the car should be taken in for service right away. If not, you can ask a local auto shop or mechanic to look up what the error code means. Then, decide if you want to fix it now or later.

Items you will need

  • Car

  • Code scanner

 How to Reset the Engine Light in a Jeep

Find the port under the driver's dashboard that fits the code scanner connector. Plug the scanner into the port, and turn the key in the ignition to the "On" position but don't let the engine start. This will cause the scanner to turn on.

Use the arrow keys on the scanner to select "Reset" or "Erase." The check engine light will turn off on the instrument panel.

Unplug the scanner, and turn off the vehicle. Wait 10 seconds then turn the engine on. Verify that the check engine light is still off.

Items you will need

  • Code scanner

  • Ignition key

  • Wrench

 How to Reset the Service Engine Light on the 2003 Buick

Open the driver's side door on the 2003 Buick and locate the diagnostic link connector (DLC) underneath the dashboard. On a LeSabre and Park Avenue, the DLC is located under the dash to the left of the steering column. On the Century and Rendezvous models, the DLC is under the dash directly beneath the steering column. On the Buick Regal, the DLC is located under the dash to the right of the steering column.

Plug the OBD II scanner/eraser into the DLC. Because of the DLC's shape and the shape of the plug, there is only one correct way to plug it in.

Place the key of the Buick into the ignition and turn the key to the accessory power position. This position illuminates the lights on the instrument cluster and powers all the accessory components without the engine running. It will also provide power to the scanner from the Buick's battery.

Press the erase button on the faceplate of the scanner. If the scanner is not equipped with an erase button, follow the onscreen menu and use the scroll or enter button(s) to the erase codes or DTCs option and press the enter button.

Allow the onscreen menu of the scanner to default back to its main menu or display a "command sent" message.

Start the engine to the Buick and check the instrument cluster to ensure the SEL is no longer displayed. If it still is on or comes back quickly, the code(s) should be diagnosed properly and repairs made if necessary.

Items you will need

  • OBD II scanner and code eraser

 How to Reset the Engine Light on a Mercedes C240

Remove the nut from the negative battery terminal using a wrench or socket set. Slide the cable off of the terminal and set it aside.

Press the horn for several seconds. This depletes any surplus energy stored in the electrical system.

Wait 10 minutes before reinstalling the battery cable.

Items you will need

  • Wrench or socket set

 How to Reset the Check Engine on a Infiniti QX4

Connect your Infiniti Qx4 to a second-generation onboard diagnostics, or OBDII, scanning tool to access the trouble codes stored within your vehicle's computer system. These trouble codes will be able to tell you -- or a repair shop -- exactly what is causing the Check Engine light to turn on. If you don't own an OBDII scanning tool, take your car to a auto parts retail chain like Auto Zone. Such stores will scan the trouble codes on your car for free.

Research the trouble codes that the scanning tool generates. Find them in your vehicle's manual or online. One helpful website is OBD-Codes.com. Some codes may suggest a malfunction with the "Check Engine" light. Others may point to a more serious problem that you should have addressed by a certified Infiniti repair shop. Do not attempt to reset the Check Engine light if the OBDII scanner generates this type of trouble code. Instead, take the SUV to an Infiniti-certified shop.

Follow the directions on your OBDII scanner to erase all the trouble codes from your car's system. This step will vary depending on the brand and model of your scanner. Employees at auto parts chain stores like AutoZone and Checkers may be able to assist with this step, or clear the codes from your car's system for you using an OBDII scanner. OBDII scanners typically have a function to turn off the instrument panel Check Engine light. Ask about this, or move to Step 4.

Disconnect your vehicle's battery to reset the Check Engine light. Leave it disconnected for 30 minutes.

Reconnect your vehicle to the battery. Turn the ignition on and see if the Check Engine light comes on as well. (You'll have to reset the clock and radio presets.)

Call a local Infiniti repair shop if the Check Engine light still comes on after you tried disconnecting the battery. A "Check Engine" light that won't turn off could indicate a serious problem with your engine that requires immediate attention.

Items you will need

  • Onboard diagnostics scan tool (OBDII)

About the Author

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