Hi ztig, I answered your other post here. in the Liberty CRD Love That Torque section.
Check the following for bad power:
Check the rubber CAC hoses going from turbo to Intercooler and from Intercooler to Intake manifold do not have any splits, cracks or holes in them.
These do fail and usually a break causes low power and lots of black smoke coming out the exhaust.
This happened to me....limped home and saw a big split in one house....taped it up with Duct tape until I could get new ones from the Agents.....this was years ago!
Most CRD owners do not use the OEM hoses but get SAMCO or Mishimoto silicone hoses...more robust and you can get different colors.....these are not available here in SA!
If you do try to get non OEM hoses as above be aware that the diameter of our Export 2.5 CRD hoses is smaller than for the 2.8 CRDs so make sure you get the correct ones.
Your Intercooler may be blocked up with oil and gunge thereby stopping the flow....I will leave it to the real experts here to advise you on how to correct this.
Make sure your MAP sensor is indeed very clean. Our 2.5 CRDs use a Bosch Map... Bosch PN is on the sensor. It is held on by two medium size Allen bolts....USA models have a different MAP held on by a single larger Allen bolt. Make sure the rubber O ring under the MAP sensor is OK.
This is a very delicate sensor...do not use brushes or cloths on it...best to spray it with Brake Cleaner.
This Map measures Boost Pressure as well as Air Intake Temperature. I had a bad wire for this second wire going from pin #2 on the sensor to the ECM....gave me major loss of power and the Engine Icon lighting up on the Right Top of the cluster...I will check which code I got.
Make sure your fuel and air filters are clean...I had a mouse make a home inside my Air Filter Housing!
Next to the air filter housing you will see a small black plastic solenoid with a small paper filter hanging down from it and a two wires connected from it....this solenoid actuates the "wastegate" and you cannot disconnect the wires going to the solenoid. You can however pull of one of the small rubber hose going to it...preferably the outer hose. Now take a small self-tapping screw and block this outer plastic nipple then re-fit the rubber hose over the screw head.
This stops the wastegate/EGR from actuating and gives you more power.
Ok I do not have 2004 Jeep KJ Service Manuals...the 2003 will be close enough but wire colors may be different.
But download the 2003 Jeep KJ Service Manuals here
but very important is to download the section: "2.5_2.8 export diesel" as it contains very useful information for our Diesels such as the Error Codes and what to do about them...tells you voltages to measure etc. but we do not have the Dealers OBIII reader that they refer to!
You can get stored CEL codes with the "key" trick:
Without starting the engine rapidly turn ignition ON/OFF 4 times.
After the 4th ON action leave the ignition ON.
The Odometer Display will read out stored codes from the oldest...which may no longer be relevant...to the newest. Codes are only stored once so multiple errors of P0123 will only show once.
You cannot erase the codes with the Key trick.
I will look into your codes and get back to you.
Read SAMS NOOB GUIDE at the top of Love That Torque section...mainly covers 2.8 USA models but some good info there...such as my EGR disable trick!
http://www.colorado4wheel.com/manuals/Jeep/KJ/These manuals give you some info. on how things work and section 8W has the wiring diagrams.
OK using the 2.5_2.8 export diesel manuals above:
P0836 Transfer Case Plausibility....this is the switch that senses if you are in 2 wheel or 4 wheel drive.
P1685.. SKIM invalid. This means the ECM was not happy with the SKIM code sent to it by the SKIM module on top of the steering column which reads the chipped code.
P0579.. Speed control switch plausibility. I presume you have Cruise Control fitted.
P0235.. Boost Pressure Sensor....could be the MAP sensor.
Go to the page number that these codes direct you to in the same manual.