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. Hey I just changed my all four tyres on 2010 jeep wrangler unlimited and it’s show low tire on computer not sure what s that mean

  2. Tried the directions way its not working for my 2010 wrangler islander so i will try from acc to on like someone suggested and see.

  3. It didn’t work the first time. Then I figured it out and did it twice and it said “done”. Light is still on. Not running funny. Going to take it to a mechanic.

  4. I have a 2004 rubicon will crank over but won’t start . It shows no codes I have replaced the crank position sensor , checked wiring , replaced computer and fuel pump still no start it try’s to fire sometimes but won’t im stumped

  5. 2008 JK 3.8 Auto. Throwing codes U1418 “umplausible right wheel distance signal received” and C1035 “right rear wheel speed comparative performance”

    Is it just the right rear wheel sensor or is it more then that?

  6. Hi fellows, my Jeep wrangler sahara 2.8 crd rough idle and stuttering, if I accelerate it picks well but puff a black smoke, now its frequently doing it.
    I took to Bosch they could find problem.

    Please assist.


  7. Hey Krag waits….did you ever figure out what was going on with your rubicon? I think I may have the same issue and you might be able to help me out.

  8. I went through these steps and got the dashes but then no codes. Just went to “done”. Engine light is still the on. Any thoughts?

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