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theksmith

Being Prepared - Jeep Wrangler JK Specific Spare Parts & Repair Info

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Now that my rig is getting up there in miles, I'm looking more into what additional spare parts I should be carrying to get the rig running again if something goes wrong while out on a trail. This is meant to cover typical parts that might fail for a JK/JKU on any type of trail (i.e. not rock-crawler type spare hard parts).

 

Also, I'm not going to cover tools and things like a jump-start box in this thread, just parts and know-how.

 

Note some of this info might also apply to a JL (newer Wrangler) or JT (Gladiator) that has the 3.6L.

 

 

Non-model-specific parts:

 

See the general list of "duct tape & bailing wire" type items you might want to carry here:

 

 

 

Owners Manual

 

It's nice to have a searchable electronic copy of the basic user manual on your phone or tablet. Download your year-specific one here:

 

 

Or a direct download for the 2016 JK/JKU manual:

 

 

 

OBD2 (check engine light)

 

The JK (like other Jeep/Chrysler/Dodge models), will show you most check-engine light codes (DTC's) in the cluster by using the simple "key trick". You just turn the key from ACC to ON 3 times fairly quickly and then hold on ON that last time. The code will read out in the odometer.

 

Here's a couple lists of code definitions that I print out and keep in the rig.

 

 

A smart phone and a bluetooth OBD-II dongle is handy as well to see other data besides just the code. That or a dedicated OBD-II code reader will also sometimes pull codes that you can't get with the key trick (like SRS or extended transmission controller related), as well as as "soft codes" that have occurred but not enough times to trip the MIL (check engine light) yet.

 

I did a large write-up with more details on the OBD-2 stuff here:

 

 

 

Basic Electronics

 

All the fuses and most relays for the JK are in the TIPM (fuse/relay box) under the hood. Inside the lid is a diagram of what they all are, but it's very hard to read. I ran across this site where someone took the time to write all that down, so I took that info and made another doc you can print out and have a much easier to read diagram and list of all those:

 

 

I was also able to find these wiring diagrams from a 2009 JK. Some of this would be specific to early JK's (3.8L engine) and so be careful about relying on the wire color codes shown here if you have a later JK with the 3.6L like mine.

 

 

Here are the Mopar part numbers or links for some things you might consider having a spare of:

 

  • Large TIPM relays: 04692139AA
  • Small TIPM relays: 68083380AA
  • TIPM Circuit breaker: 4692143AA

 

 

  • Other relays: Outside of the TIPM, JK's have a few other relays in the engine bay. In any Rubicon, two of them control the lockers. In the 3.8L JK there are 2 that control the low and high speeds on the cooling fan. My JK has 2 more that I've still got to find out what are for! There is a specific part number for the double ones (2 joined by a single mounting bracket), but any one of them can be replaced with part # 56055667AB. In fact, inside the waterproof housing, they all seem to all be a standard automotive 5 pin 12v relay.

 

 

Basic Spares

 

  • Serpentine belt: Part # 4627043AA for the 3.6L
     
  • Idler pulleys: Super common failure item, the 3.6L has (2) of part # 4627039AA.

    Both the 3.6 and 3.8L without air conditioner, have a third idler: part # 53034002AA.
     
  • Radiator cap: Cheap, small, and critical - might as well carry a spare: part # 4596198.
     
  • Radiator hoses: The actual hoses on the JK are pretty big, so I don't carry those but instead have a radiator hose repair kit (which includes splices for the heater hoses).
     
  • Starter: They typically last well over 100k miles, but with an automatic I can't push start the thing and so a dead starter will leave me stranded. Since it's a relatively easy part to replace trail-side and not too big of a part, I do keep a spare. The part # for a 3.6L starter is 56029852AA (check eBay).

    It's worth noting that if your starter seems to have gone out, sometimes a tap with a hammer or rock will get it going again to get you off the trail. Be sure to check that it's not just a loose or corroded connection (or a weak battery) before resorting to violence though!

 

 

What am I missing?

 

I don't think the JK has any super common sensor issues (like that crank position sensor on the old 4.0L engines).

 

The only semi-common failure I've heard of on the 3.6L is the oil-cooler, but that's not a trail-side repair. I am considering pro-actively having it replaced soon. I replaced the serpentine belt and idler pulleys not long ago, I may also go ahead and do the radiator hoses and cap.

 

Does anyone know of:

- any other common failure points with the JK or 3.6L engine?

- other items to proactively replace at 100k miles?

 

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I should do one of these for Jeeps with the straight 6 in them. Great post, K!

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Wow this is great info! I was recently thinking about this the other day when looking at buying some spare u-joints (since I’m stock) and some other items. This is a great starting point for me!

 

Thanks man!!

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Posted (edited)

I read through both posts from theksmith and they are both great!   Two items I recently added to the Jeep are a fuel pressure gauge ($25) and spark tester ($5) from Harbor Freight:

 

62623_zzz_500.jpg.059ffaeff7c7062bef5a02f730851ca2.jpg63590_I.jpg.de4b1d6d44bf7e2c2829d34fa99af843.jpg

 

https://www.harborfreight.com/fuel-injection-pump-tester-62623.html?_br_psugg_q=fuel+pressure+tester

https://www.harborfreight.com/in-line-spark-checker-63590.html

 

There are some complaints that the fuel pressure gauge leaks, but it worked fine for me when I replaced my fuel pump.    You can also use the Harbor Freight coupons to knock another 20 percent off of the advertised prices.  :) 

 

Thanks.

Edited by gearhead
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This applies to all vehicles but I just helped a friend change out their rotors on a JKU and the bracket that holds the caliper has two bolts which are 18 mm. If you have the need to access your axles this 18mm will help you get there. Point is, carry a 18 mm wrench or travel with someone who does.  John

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12 hours ago, johnpa said:

This applies to all vehicles but I just helped a friend change out their rotors on a JKU and the bracket that holds the caliper has two bolts which are 18 mm. If you have the need to access your axles this 18mm will help you get there. Point is, carry a 18 mm wrench or travel with someone who does.  John

 

very true, many wrench sets skip 18mm for some reason and there are actually quite a few bolts you need one for on a modern Jeep.

Edited by theksmith
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