The powertrain control module (PCM) in your Jeep Wrangler – often referred to as your engine’s “computer” – acts as the brain of your vehicle’s engine.
More specifically, the PCM in your Jeep is actually a combination of two other computers: the engine control module and the transmission control module. Although it may appear like a single unit from the outside, it’s actually made up of these two separate units, housed together in a single module.
Think of your Wrangler powertrain control module as a computer, similar to a laptop. On the inside it is a combination of circuits and wires that relay and store important data and information. Much like the computer you’re probably reading this on, PCM function is determined and controlled by software that allows it to work seamlessly with your particular vehicle.
What Does a PCM Do In a Jeep Wrangler?
Your Jeep Wrangler powertrain computer controls literally hundreds of functions and processes within your Jeep’s engine. This can include everything from controlling when your transmission shifts gears to fuel injection parameters to determining when to activate your check engine light. Needless to say, if your Wrangler’s central computer is not functioning properly, your Wrangler is not going to be running properly either.
Among other symptoms, signs that your Jeep needs a new PCM include the following:
- Check Engine Light – The light goes on and off and doesn’t seem to correspond to an actual mechanical problem.
- Engine Stalling or Misfiring – Stalling and misfiring may occur without any pattern regarding frequency or severity.
- Engine Performance Issues – You’ll notice a reduction in fuel efficiency, power, and acceleration.
- Car Not Starting – Your vehicle does not start or is difficult to start. The engine may still crank but won’t be able to start without vital inputs from the computer.
Jeep Wrangler PCMs for 2005-2006
There’s a very common issue with control modules in 2005 and 2006 Jeep Wrangler models. If you keep your Jeep long enough, you’ll probably encounter a situation where you’ll need to repair or replace your Jeep Wrangler PCM. If you ever notice any of the above signs of a failing Jeep Wrangler PCM, you will want to have the issue checked out to see if the problem is actually the powertrain control module.
When it comes to 2005 and 2006 Jeep Wranglers, there’s a strong chance the PCM is to blame.
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TJ Wrangler Model
The TJ Wrangler model produced between 1997 and 2006 was a popular vehicle. It widened the Wrangler’s appeal by offering a smoother ride and more comfort, safety, and entertainment options—features that all add stress to the PCM. This model of Jeep Wrangler was so popular that over 965,000 were produced between 1997 and 2006, with over 175,000 TJ Jeep Wranglers produced for model years 2005 and 2006.
Put simply: there are a lot of these vehicles currently on the road. The problem is, despite being extremely popular, Jeep TJ Wrangler models weren’t without their issues. You can check out any Jeep forum online and see that 2005 and 2006 Wrangler models are notorious for having a host of PCM problems.
From the stalling, misfiring, and other performance issues stated above, to problems with engine temperature readings and false engine error codes, the headaches that come from a failed PCM are significant – and frequent.
Causes of a Jeep Wrangler PCM Failure
There are a variety of reasons why your Jeep PCM might fail. One of the primary ways is because of physical damage. This can be caused by environmental factors – like corrosion, thermal stress, vibrations – or if the computer is submerged in water or mud while you’re tearing off road. You could also have a voltage overload if there’s a problem with your Jeep’s power supply or wiring, or alternatively, you might have just gotten unlucky with a poorly manufactured PCM.
However, if the problem with your Jeep Wrangler PCM has no discernible physical cause, there’s a chance it might be an issue with the software.
Reflashing 2005 and 2006 Wrangler PCMs
When you have an issue with, or even a failing powertrain control module or engine control module, oftentimes there’s a problem with the software and you have to get it reflashed. Reflashing your Jeep Wrangler PCM is a tuning technique that is also often called flashing, remapping, or flash tuning. Reflashing is not just for bad PCMs either; you can also reflash your Jeep Wrangler to get the latest software and/or updates from the manufacturer.
Like any computer, your car’s PCM or ECM has software with different settings or parameters, and these can be changed to alter the performance and driving limits of a vehicle. Reflashing or remapping an engine computer is essentially just the process of replacing the existing software in a vehicle controller with new software.
The problem with reflashing a 2005 or 2006 Jeep Wrangler, however, is that the post-flash computers have a very high rate of failure once completed, regardless of where you get it reflashed at. Although there are numerous reports of 2005-2006 TJ PCM problems (both with the original PCM and software, and with difficulty reflashing), there has, unfortunately, never been a recall, legal action, or support from the manufacturer. This has left many Jeep owners without options.
Fortunately, CarComputerExchange.com can help you with your 2005 – 2006 TJ Jeep Wrangler PCM problems. They’ve developed a thorough, custom process that greatly diminishes the fail rate that many owners experience when they reprogram Jeep computers: click here in order to learn more about the site’s offerings.