Replacement of the PCM (Powertrain Control Module) in Jeeps is in great demand these days, because there seems to be a rather large rate of failure for these automobile microprocessors in the US.
So what is a PCM and what is its function in your Jeep?
The PCM, called the JTEC or Jeep/Truck Engine Controller, like its name suggests is positioned in the engine. This triple microprocessor is digital and pre programmed. The PCM controls the ignition timing, emission control, fuel systems, air-fuel ration, charging system, speed control, idle speed and air conditioning.
The PCM gets inputs from a number of sensors and switches and acts on the inputs to regulate the working of the engine. The programming is adapted to changing climatic conditions.
How well a vehicle performs is dependent on how good the powertrain is. Vehicles with automatic transmission are totally computerized and the computer will indicate when the gears have to be shifted. In manual transmission vehicles, the driver learns through trial and error when to change gears to get the best possible mileage and performance from the vehicle.
Off roaders will find that they can fine tune the transmission shifting points and the engine by slightly tweaking the software with an electronic device which is connected to the Jeep PCM. This really helps driving when they off-road.
If the Jeep PCM fails, then there will be a number of problems; error lights will appear on the dash, there will be electrical issues and in most parts the Jeep will not run properly.
However, most problems of the Jeep PCM are rooted in some common faults. The first one is when there is surplus voltage. Sometimes there could a short circuit in the supply or wiring. If the vehicle gets a shock then the PCM will be affected. Too much of power can burn out the PCM. This happens in general with the actuator or solenoid circuit.
Corrosion, vibrations and thermal stress are also factors which can adversely impact your Jeep PCM. A word of warning to off-roaders; if the PCM gets water logged or bogged in mud it will result in failure.
Some cases of failure have been attributed to a manufacturing defect. So if you have the misfortune to get a faulty PCM and your Jeep is not too old, better replace the PCM.
There are a lot of places where you can find high quality PCMs. Some of the better online stores and dealers offer you trained engineers who will build up the Jeep PCM and program it to your vehicle.
The PCM then under goes some very stringent quality control tests and is measured against the OEM (original equipment manufacturer) standards. This is not a difficult task. You will need to give them the mileage and the VIN (vehicle identification number) of your vehicle. This will ensure that the PCM is calibrated properly and will easily facilitate plug and play. So once the Jeep PCM is fitted you will be on the road again.