How to Read Jeep Wrangler Check Engine Light Codes Without a Scanner

By | February 3, 2022

How to Read Jeep Wrangler Check Engine Light Codes Without a Scanner
If you have a check engine light come on in your Jeep Wrangler, built-in diagnostics can show the code.

After the code is read, it can be Googled to find the problem.

The steps are simple by cycling the key from Off to On three times, and the code will flash once on the dashboard LED.

Do not start the vehicle; only turn the key to the On position.

How To Check Engine Light Codes on a Jeep Wrangler Without a Scan Tool

  1. Turn the Key from OFF to ON three times.
  2. The last turn of the key should be in the ON position.
  3. The code will show for only a moment and flash P-done before going back to normal.

Here the code P0520 is displayed on the right below Park, Reverse, Neutral, and Drive.

Typing P0520 into Google shows that it is an Engine Oil Pressure Sensor.

This method may not work for all Wranglers, and there are many low-cost scanners that can give the codes along with more information.

Most automotive stores will also do a free scan and give the code; if a scanner is not available, be sure to call a store first.

If this method works for you, let us know in the comment below, as it is a good quick way to troubleshoot a jeep in a pinch.

10 thoughts on “How to Read Jeep Wrangler Check Engine Light Codes Without a Scanner

  1. Zoe Varga

    Will this method work on older models as well and if so how early does it go?

  2. Christine Callahan

    I did try this a couple of times. One time it did register “done” but the 2 other times it just read a bunch of dashes(——) and then back to the mileage. Am I doing this wrong or is it something else?

  3. Linda

    I have an 07′ jeep wrangler sahara. I tried the off/ on position 3 times, no code. I also tried the on/aux on off 3 times, still got nothing. What am I doing wrong?

    1. Hillis.

      You have to turn key until you hear the ding ding and all 3 times must be done rapidly back to back. Hope that helps

  4. Jennifer

    What if you dont have a key? Is there a way to diagnose jeep codes for keyless start? (2014 grand Cherokee limited)

    1. Jennifer

      Update or continue to my previous post/question….diagnosing keyless entry jeeps
      My question is referring self diagnosing jeep codes. Meaning besides having to go to an auto parts store or a mechanic simply to find out why my engine light is suddenly on, not flashing, but on.


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