This is a technical bulletin from John Brain South, founder of ECMtoGo.com and Auto Computer Supply in Houston in 1997, and Auto Computer Pro in Miami/Ft Lauderdale in 2012. This Technical Bulletin pertains to 2005-06 JEEP WRANGLER Engine Control Computer PCM Failures. Jeep Wrangler Sport or Rubicon 4.0 liter Auto Transmission.

PART NUMBERS: P56044529AH P56044528AC 56044529AH 56044528AC P56044702 56044702AD P56044703AD

Hello from ECM TO GO- Auto Computer Pro to all the Techs out there and proud Jeep Wrangler owners! So glad to be able to pass on some of our experience and expertise in Engine Control Computer Diagnostics, Repair and Replacement. In todays tech bulletin BLOG, I am going to discuss the technical issues that lead to a high failure rate of the 2005-06 Jeep Wrangler PCMs specifically for the 4.0 liter models with Auto Transmission. The signs of a failing PCM are anything from a “Hard Code” MIL CEL that can not be cleared. These may be codes related to the automatic shifting or a number of codes that seem random. Often we see a hard shift from 2nd to 3rd gear. You may also have No Start and No Communication. The first thing to do is scan for communication and check for stored codes. Be sure Charging system is Good. Many times we see problems with the transmission shifting. They are often caused by harness failure or shorting. This is a common problem with the 2005-06 JEEP Wranglers. Any low voltage events can damage any ECM (Electronic Control Module) including the PCM. Any shorts such as inverting battery or short in Power or Ground, short in Alternator can affect the PCM and other ECMs. Wiring Harness shorts are a common problem due to the Engine shaking and the Mounting Brackets rub against the Harness for years until insulation is compromised or damaged which can lead to voltage loss or shorts.

It is recommended that all PCM Diagnostics / Removal / Installation must be made by an Authorized Certified JEEP Repair Technician for your manufactured vehicle. Refer to our website or the Featured BLOG PIC for PCM location and removal instructions. If needed, we can do a verification test the computer for you here at ECM TO GO Auto Computer Pro. Once it is verified there is an issue with the PCM, we can assist with a Plug and Drive fully programmed replacement PCM. Any and All Problems with the vehicle must be repaired and resolved before re-installation of a Replacement PCM.

Thanks for your time and I hope this has been helpful. ECM TO GO has been on line and supplying Dealerships, Repair Shops and Do it yourselfers since 1997. If you have any questions, please email or call ECMtoGo.com ECMguys@gmail.com 954-903-8076. You can email me direct at JohnnyBrainBox@gmail.com