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. After backing up with my emergency break on my engine light came on and I got a P0202 code. Could this be a misfire because of the e-brake being on? Last week I changed all spark plugs and have ridden about 300 miles since with no probs. Thanks.

  2. While off-roading in the dunes today the computer gave me a warning message: Engine Oil Hot. Check the oil, everything seemed fine, engine was not overheating, etc… Got out of the dunes just in case, and on the highway everything fine. Not abel to find anything in the Owner Manual. What is it and what am I supposed to do? Service Center is closed for next 4 days.

  3. it means you were over heating your transmission. when the light comes on, you need to stop your jeep but leave the engine running for a bit, this will help cool things off. to help prevent it from coming on in the first place, you should use lower gears.

  4. I have a 2005 Jeep Grand Cherokee, and my airbag light is on. I pulled the codes for it and its U0151(Lost Communication with Occupant Restraint Controller ORC)What do I need to do to fix this? Where do I begain?

  5. jeep won’t engage 4×4 in eithe high or low. Trouble code given is the C1405 TRANSFER CASE RANGE POSITION SENSOR CIRCUIT HIGH. What the crap does that mean exactly and how do I fix it?

  6. Anyone ever had the dealership tell them something is wrong and when you run the diagnostics on the vehicle, nothing pops up? Base auto hobby shop said it was the O2 sensors, the dealership says it’s a catalyst efficiency fault, and the vehicle shows nothing.

  7. I just picked up the error code on my JK, thanks for the tip, very useful. The only error that it gave me was P-0455 Evap purge system large leak. Any comments on what could it mean or how to fix it? Thanks!

  8. P2181-Cooling System Performance
    2009 4 door X Unlimited 49,000 miles

    Coolant Overflow at minimum
    Temp Gauge working differently. (Bouncing,running warmer)

    Is that the cause, possibly?
    What might any other immediate causes create these conditions, at this mileage?
    Thank You in advance.

  9. Is this the right place to post a question for troubleshooting??? I tried to use the method above to find some answers but no codes were given. That being said, I still have the same problem and have had so for about 2 wks now. My pass side rear turn sig doesn’t always work. I checked the bulb (was good) but replaced it anyhow, checked for loose wires and poor contact. All was good. A Mech. friend checked online and said that it looked like the computer wasn’t sending a sig to the light/plug. To me, if that were true, shouldn’t that throw a code??? Like I said, sometimes it works and sometimes it doesn’t. Any help would be great.

  10. Guess I should have said that it’s a stock 08, 2dr, X modle. Sadly enough to say that the only off road it’s seen is my 1/2 mile dirt road for the past 3 yr that I live on.

  11. Still cannot get codes to show up. I placed key to on position, pushed it in, while keeping it pushed it switch to Off, then ON, then Off, then ON, then Off, then ON. Dash lights up, but I do not get the dashes —– All I get is the CEL flashing for a few seconds and GASCAP error…no related codes. Am I missing something?

  12. I’ve been having C121E–BRAKE PRESSURE SENSOR COMPARATIVE PERFORMANCE. The ESP/BAS lights have been on for a week or so. What exactly do I need to check to get this fixed?

  13. abs light esp bas light andtraction control symbol light up and stay on.fault codes u1418 and c102b showed. what do these mean.

  14. I have a jeep wrangler sport 2003, codes p0301, p0302, p0305, po201, po203, po205. These codes done come up all at once though. A set like po201 and po301 will come up, ill clear the competer and after a few hundred miles another set of codes will come up for a differnt cylinder. Iv changed the spark plugs, the coil pack/plug rail. Iv checked all wires with ome meter. I am wonder if i should change the pcm out but im tired of throwing money away. What do you think?

  15. I have code C1210 according to my superchips programmer. I try clearing it and it always shows its ugly face again. the code says something along the lines of “G Sensor Input Performance”. My abs, traction and esp/bas light show up on the dash. I NEED HELP!

  16. Code C1210 “G Sensor Input Performance” shows up. ABS,Traction control, and ESP/BAS light are all on. Anyone have an idea?

  17. I received an error code of P0300 for my 2012 Jeep Wrangler Sahara Unlimited. Can anyone let me know what this means. Thanks.

  18. On my 07 if you press the key in trying to look for codes turning from acc-run three times it wont read the codes but if you do it with out pressing in the key it will read and show if there’s a code

  19. Where is the list you mention that’s at the bottom that shows the faults 00-99? I have a code PO113. What’s that all about? power train, SAE, FUEL & AIR METERING AND FAULT 13. PLEASE HELP.



  20. Dear Sir
    I have the first 4 door rubicon wrangler released I live in south Africa so service centers are few and far between
    I have tried the tip with the key all that remains on is the engine warning light no codes no done . I have a uni chip fitted will this effect the process you describe ?
    Also the jeep can run for for like 800 km’s and then the warning light switches on slippery surface and drive by wire and performance drops and the gas usage becomes high when you are hundreds of miles from anyone it can become a problem.
    Most times if I leave it off for a while and start it up all the lights are off and it’s back to normal.
    I have 67000 km’s. Any suggestions.
    Thank you

  21. I have a trouble code P 1060 and my engine light is on solid. Can anyone help. Just had new head gasket put on and my mechanic said it has something to do with the oxygen sensor. Any body want to confirm or deny that? HELP please. This car has been a nightmare.

  22. i had a gas cap showing bad on my 2007 so i replaced it and reset code after about 50 miles light came back on again and now show a p0440 code what is that?

  23. I have a 2001 Jeep wrangler, new moter installed about a year ago, engine light came on, fault code is P0138, can you tell me what it is? Do you email the answers? Thank you

  24. I have 2007 wrangler unlimited and as of recent a week ago the speedometer will drop to 0 from any speed while it flash (brake-abs-esp-esp pic) but the engine will remain full power like it nothing going on and just a day ago engine light came on went to get code pulled it said p0573 while is brake switch 1 stuck off but when i follow ur step it show done with no code read is it common for speedometer to drop like that just over brake switch?

  25. My check engine light came on. 2008 JK Wrangler. I get the dashes and then the “done” message, but no error code. I took it into Chrysler and they got a P0303 code. Any reason why I did not get a code, but Chrysler did..?

  26. I have 2008 JK Rubicon and tried getting the codes through the above method…but nothing. Then found I only have to to do two cycles quickly instead of the three. But unfortunately got the -done- message with no error code. Then it finally clicked in that I had removed my battery that day and cleared the codes. Then after got it going I drove it around the blocks a couple times and got the codes P0513 & P2503.OMG! Any ideas?

  27. I have two codes. First reads P2181 cooling system performance. Since I did my mods I’ve been having cooling issues. Good on the highway or in town or on flat trails but as soon as I start going up hill on the trails I start to heat up. I just installed a BeCool electric fan and it’s not as bad but I’m still getting quite hot (75% of the gauge) going up long steepish hills. I also have an electric transmission push fan as well. Second code came up yesterday on the trail. I was at the top of a mountain range when my charge light came on, my temp gauge quit (went to zero) and the electric fan didn’t quit until I got home and shut down the vehicle. Code reads P0218 high temperature operation activated. Ever had this come up? Is it a concern? What do the Project JK rigs run for cooling? Any help here is appreciated as none of our local tech’s seem to have any idea.

  28. i have a 2012 jeep wrangler unlimited and the check engine light came on, code PO302= cylinder 2 misfired. what doe shtis mean

  29. have a 2004 jeep wrangler rubicon 2 dr with a diagnostic code of P0122? read the I have no idea what the code means? Plz help, have 80,000 Plus on her, Third owner

  30. My son has a 2007 jeep wrangler unlimited. It always runs fine when 1st started. When turned off for a few minutes and restarted, it runs as if a spark plug has been pulled and running on a few cylinders. The code is for cylinder / injector mis-fire. Replaced the injector and still runs bad after being turned off for a few minutes. Help please. Any ideas what’s causing this? Ronnie….

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