Jeep JK Wrangler Diagnostic Trouble Codes
DTC How to Check Them

Thanks to the advent of technology, just about every single part on your new Jeep JK Wrangler is wired up to a computer. And, if anything goes wrong with any one of these parts, your Jeep’s computer will make a note of it and/or even let you know about it by illuminating a Malfunction Indicator Light (MIL for short or ‘check engine’ light) or icons on your dash. Unfortunately, the MIL or other icons won’t tell you a whole lot other than the fact that your Jeep is having some kind of a problem and unless you take your Jeep into the dealership or have a OBDII reader handy, you’re pretty much out of luck, right? Wrong. As luck would have it, the JK Wrangler’s come with a Diagnostic Trouble Code (DTC) reader built right into the dash and you can access them by following the 3 simple steps below. Once you have the DTC code(s) in hand, check it/them against the list below and you will be able to find out exactly what problems your Jeep is having.

How to Read a DTC

A DTC or Diagnostic Trouble Code is made up of 5 digits the first of which is one of the following letters:

B – Body
C – Chasis
P – Power Train
U – Network

The 2nd digit indicates:

0 – SAE
1 – MFG

The 3rd digit indicates:

1 – Fuel & Air Metering
2 – Fuel & Air Metering
(Injector Circuit)
3 – Injection Systems or Misfire
4 – Auxillary Emissions Control
5 – Vehicle Speed Control
& Idle Control System
6 – Computer Output Circuit
7 – Transmission
8 – Transmission

The last 2 digits indicate:

Fault (00-99)



1. To check your Jeep JK Wrangler’s DTC codes, simply insert your key into the ignition, turn it to the ‘ON’ position but do not start the engine. Then, push the key into the ignition cylinder and while holding it in, turn it to the ‘OFF’ position and then back to the ‘ON’ position (3) times straight making sure to end with it in the ‘ON’ position. It is important to keep pushing in on the key to prevent it from catching at the different positions along the way.
2. If you do step #1 correctly, all your dash lights will illuminate and your odometer will show up as a series of (6) dashes as shown in the pic to the left. If your Jeep JK Wrangler has any logged in any DTC’s, they will be displayed soon after the dashes appear. Write down the DTC(s) and check it/them against the list below to find out what they mean.
3. If your Jeep JK Wrangler has not logged in any DTC’s, the dashes on your odometer will be followed by the message ‘-done-‘. Turn your key to the ‘OFF’ position and you will in fact be done.

Click here to see what your code means: DTC Codes List


  1. From what I can tell, both P0017 and P0018 are the same as P0016 – Crankshaft Position – Camshaft Position Correlation, except that 17 refers to “Bank 1 Sensor B” and 18 refers to “Bank 2 Sensor A”. Unfortunately, I do not know what P00D4 is. Sorry.


  2. Thanks for posting this! Hopefully I won’t need it for some time, but I’m sure this will definately be useful in the future

  3. If you take things literal, there is no “OFF” on the ignition switch. You have “LOCK”, “ACC”, “ON”, and “START”. Follow the instructions above, but cycle quickly between ACC and ON. Works for me every time.

  4. OK I have tried this SEVERAL times and it does not work ! WTF ??
    Even when the key is pressed into the ignition I can still feel the detent positions between off (lock) and on….the key does not stop at the detents, it’s just that I can feel that they are there. Is some thing wrong with my ignition switch? Does this work on all JK’s? I have a 2007 2 door Rubicon 6 speed that I purchased in Feb-07. got any tips??

    Thanks, Paul

  5. Hey Paul, feeling the positions is normal. Did you make sure to start from the on position (last spot just before your starter begins to crank) and did you make sure to do this rapidly? Also, did you try what AZJeeper suggested?


  6. Thanks SO much for this. I have had check engine lights come on no less than 10 times .._ this is quite annoying for a JEEP 6000 miles on it. CHECK ENGINE… what in the H_E Double_Toothpicks is that supposed to mean? This should be i the owners manual.

    Thanks Again. Ev

  7. Hey,

    Thanks for giving us backyard mechanics the info….

    I hate taking my baby into a dealership, or worse a mechanic….UNHHHHHH

  8. To reset your codes, you can disconnect your negative battery lead for about 5-10 min. When you hook it back up, they will be gone and your computer will start learning again from there. Or, if you have something like a Hypertech Max Energy Power Programmer or ACCU-Pro, they can clear out your codes as well.




  10. I had a P0018 code, though all 5 of my tires are at 26psi (35″) and yet none of the low pressure DTC’s were shown on my Hypertech even though the TPMS dash light stays on every time I start the vehicle.

  11. Hi, I connected the Hypertech power programmer and got U0154 LOST COMMUNICATION WITH OCCUPANT CLASSIFICATION MODULE …… wonder what should this mean????

    Thanks in advance

  12. i just bought a new wrangler unlimited rubicon in indonesia. i cannot find how to deactivated the function when i unlock the door from the remote control the headlamp is on automaticly for about 1 min. thank you for ur help

  13. I got 3500 miles on my 2008 Wrangler Unlimited X and it kept telling me to change the oil. I finally got a check engine light and changed the oil after that. Went through this procedure to find out why the check engine light came on. It seemed to work great and all it says is “change oil”…no code. Is that normal?

  14. I have several codes not on the list. All of them have the 3rd digit as ‘0’ which isn’t on the lists above. They are all ‘P00xx’. Is there a portion of the DTC list not printed here?

  15. i have a hypertech max energy power programer and the dtc code that can up was P0000 can you tell me what this means thxs

  16. P0562 System Voltage Low does this mean that I need to change the batteries on a 2007 4 door wrangler?

  17. this is great news.
    my old 90 daytona has the same thing where i can check the codes now i can do it with my jeep too!! yay

  18. Has anyone in this forum ever get codes P0203 and P0303 at the same time and how did you fix the problem? Thanks in advance.

  19. azjeeper’s suggestion worked for me.

    Start in the ON position. Then cycle back to ACC and up to ON three times fast (within 2 seconds or so), ending in the ON position.

    I’m having intermittent starter issues. They replaced the ECM (I think) a while back when it wouldn’t start at all, and now have ordered a WCM.

  20. I had a hot oil warning after running in soft sand, I’m assuming it meant trans as the water was normal and that a extra cooler will keeping it from happening. again

  21. I just bought a 2009 wrangler and as soon as I got home a “hot oil” indicator light came on? I cannot find this issue in the manual…please help!!

  22. I got the p2504 code, which is charging system output high, I checked the output to the battery and it was sitting right below 14.4 volts which is right where it should be. Just wondering if i could get a little more info on this issue if at all possible. Thank you

  23. Hi Everyone,
    I have a problem with my instrument cluster. For no apparent reason, the cluster had no power to it one morning when I started up my 07 JK. I disconnected the neg terminal on the battery and waited approximately 10 minutes. Reconnected. Dome light came on, instrument cluster had power. As soon as the dome light timed out though, instrument cluster lost power again. Checked schematics and am down to the “immoblizer” circuit. Is this something that I have to take to the dealer to get checked out on thier diagnostics?

  24. HOTOIL – part of a recall I just had to do. Turns out they’ve discovered that the Auto Transmission isn’t really good enough for the Jeep (Surprise). So instead of giving everyone a nice new Tranny cooler… they just added a fancy light to tell you the Tranny is hot.

    They include an addendum to the owners manual – when the HOTOIL indicator lights, pull over and idle in neutral until the light goes out. Then carry on… nice of them huh?? (I ain’t kiddin’)

  25. Hi guys I need your help- My baby is pulling the code P0016 crankshaft/camshaft timing misalignment (2005 Wrangler Sport) and we have replaced both the crankshaft and camshaft sensors ($70.00 later) and it continues to pull the same code. I have done the research and have found the there was a service bulletin issued (E05 or NHTSA Item# 10013784, Oil Pump drive gear may wear out prematurely and cause engine failure due to loss of oil pressure) but I have not have a problem with losing oil pressure. Can anyone tell me if an Oil Pump Drive Gear is the same as an Oil Pump. I am thinking that it is not and that the Oil Pump Drive Gear is probably located somewhere around the camshaft but I am not sure. Can someone please tell where it is located and how hard to replace on my own without having to take it to a shop. Thanks so much in advance for all of your help and experise 🙂

  26. I’ve had the engine light come on about 4 times lately. Drive it for awhile and it goes of. Drive it again a couple times and it comes on again. Decided to check code this time. it is:

    And this means…???

  27. So both my battery and my alternator both went out on my 07 jeep jk…I thought? I replaced both of them and now I am getting all kinds of electrical trouble. When I am driving my cluster goes nuts…speedo and tach both start bouncing and every possible engine light comes on. I checked this with my Hypertech programmer and I got the following code, some of them are listed here but others are not. P0000, U0001, P30D1, P1330, U1403, B30D1, P0CB0, U110E. Please I need some help. Thanks

  28. HELP pls
    i did the diag. i get the words DONE but the electronic throttle control light stays on for a couple secs. could this be my kille. The 07 jeep wont start, it clicks. I tried disconx the luck.. Battery has plenty juice. i tested it . pls help

  29. Hello. I just bought a 2001 Jeep and after 200 miles engine light is flashing. Diagnosed the following things: P0202, P0302, P1281. Is this reason for concern? What do I need to do? Do I need to bring it in for servicing already? Thanks!

  30. Hello, our 2006 Wrangler Sport will turn over but not start. The Fault code reads P0522, which is the Oil Pressure Sensor reading low. Suspecting the sensor might be bad, I replaced it, but the engine will still not start. Same fault code reads out. Am I missing something or am I really looking at a failed oil pump or failed oil pump drive? Should something be reset to allow the engine to start?

Leave a Reply

Your email address will not be published.