How to Check the Codes on Vehicles

by Contributing WriterUpdated June 12, 2017

If the "Check Engine" light comes on and remains on after the Vehicles has been started, it indicates a problem with the emissions and/or fuel injection system. You will need to check the ECU (Electronic Control Unit) Vehicles diagnostic trouble codes (DTCs). This model uses the check engine light to flash trouble codes. A common mistake is to assume that the part indicated has failed--a trouble code could simply mean that the electrical circuit Vehicles the failed part has a problem and is not functioning properly.

Under The Hood:

 How to Check the Codes on a 1994 LeSabre

Unbend the paper clip into a "U" shape.

Locate the diagnostic port on your 1994 Buick LeSabre. It is located under the dash on the driver's side. The diagnostic port contains 16 pins in two rows of eight.

Insert the bend of the paper clip between pins five and six. They are not marked. Begin at the left on the top row, and count over five pins.

Insert the key into the ignition and turn it back until it clicks. The check engine light will blink in a specific pattern--a series of blinks with short pauses, followed by a longer pause, then another series of short blinks. Write down the numbers produced by the blinking check engine light. For example, if it blinks twice, followed by a pause and four blinks, write down "24." The OBD system will repeat each code three times before giving you the next number. Each number corresponds to a diagnosis, which can be found in your service manual.

Items you will need

  • Non-coated paper clip

 How to Check Codes on a 1995 Ford F-150

Plug a scan tool’s data-link cable into the 1995 Ford F-150's diagnostic port. The port is located underneath the driver’s side of the dashboard; it has a small, black cover over it to protect it from contamination. You will need to remove the cover by hand to expose the connector’s pins, which mate to the data-link cable.

Turn the ignition key to the run position and turn on the scan tool if it does not come on automatically after you turn the ignition key.

Follow the scan tool’s specific operating instructions for running a self test on the F-150’s power train control module. This will reveal the trouble codes that have been stored.

Write the codes on a piece of paper for reference during the diagnosis and repair stages.

Clear the codes when prompted to do so by the scan tool if the malfunction has been corrected. Do not clear the codes until you have repaired the malfunction. Doing so will simply give the power train control module a rudimentary form of amnesia and make diagnosing the issue more difficult. If you need to disconnect the scan tool and diagnose the issue later, simply decline to erase them when prompted to do so, and finish out the self test.

Disconnect the scan tool when the test is complete. Don’t forget reinstall the diagnostic port cover when you are done.

Items you will need

  • Scan tool

  • Ignition key

  • Paper and pen

 How to Check Codes for a 1990 Honda Accord

Locate the service connector under the right side of the dash, below the glove box. It is located beside the passenger door, and it should be blue or green. This connector has two terminals.

Unfold the paper clip to straighten it out. Bend the paper clip into a large "U" shape and insert one end into each of the terminals on the service connector.

Turn the ignition on without starting the car.

Watch for the check engine light to flash. Codes 1 through 9 are shown as a series of short flashes. Two-digit codes are shown with a long flash for the first digit and a short flash for the second digit.

Write down the codes that you find. Count them several times for accuracy. Multiple codes are alternated: A code 4 and 15 would be shown as four short flashes followed by a pause, then one long flash and five short flashes for code 15.

Items you will need

  • Pen

  • Paper

  • Code chart

  • Paper clip

 How to Check Codes on a 2000 Dodge Durango

Check Trouble Codes

Sit in the driver seat of your Durango. Insert the key into the ignition.

Turn the key to the “ON” position, then quickly turn it off. Repeat the process. Turn the key to “ON” and leave it.

Watch the odometer display area for engine codes. The codes will flash, and will be four-digit numbers preceded by a “P.” Each individual code will flash, and then “PDONE” will appear after the last code.

Turn the ignition key to the “OFF” position. Remove the key from the ignition.

Clear Engine Codes

Raise the hood of your Durango. Disconnect the negative cable from the battery using a wrench.

Insert the key into the ignition, turn the key to the "START" position, leaving it for 15 to 20 seconds. Turn the key to the "OFF" position and remove it from the ignition.

Connect the negative battery cable, tightening the connection with a wrench. Close the hood of your Durango.

Items you will need

  • Ignition key

  • Wrench set

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