First off, can you get the vehicle running at all? If so, what is your voltage tested at teh battery with the vehicle running? It should be around 14v (14.4v is normal)
If you cannot get it started on its own power, you may want to jump your vehicle w/ annother and see if it runs better/starts at all. If so it is definately related to low voltage. If not look into the lost communications code further.
I think the code you are referring to (lost communications with gateway "a") is a U0146 - and more specifically "lost communications with central gateway". This is based on gmctd's post here:
http://www.jeepkj.com/forum/showthread.php?t=38115At this time I do not know anything more on that code other than it is a network communications code - I will look at service manual when I get home. It may very well be an internal circuit in the engine control computer. It may also be a bad connection at a major intersection of the wiring harness(but I am just guessing here).
Also found this thread from someone who had this issue back in 2008:
http://www.jeepforum.com/forum/f28/help-obii-u0146-how-do-i-fix-749331/This thread also lists this info:
Quote:
A DTC or Diagnostic Trouble Code is made up of 5 digits the first of which is one of the following letters:
B - Body
C - Chasis
P - Power Train
U - Network
The 2nd digit indicates:
0 - SAE
1 - MFG
The 3rd digit indicates:
1 - Fuel & Air Metering
2 - Fuel & Air Metering
(Injector Circuit)
3 - Injection Systems or Misfire
4 - Auxillary Emissions Control
5 - Vehicle Speed Control
& Idle Control System
6 - Computer Output Circuit
7 - Transmission
8 - Transmission
The last 2 digits indicate:
Fault (00-99)
Based on that, it is a Network code, SAE (don't know what this means), Issue is in the fuel and air metering area. May be related to a circuit that relates to fuel/fuel delivery
Check all connections under the hood and look for damage. Disconnec and reconnect connections you can gain access to that have to do with fuel/air delivery for a start. Then maybe go to more main connections. This definately sounds more electrical then air in the fuel.
I believe there is a large connector at the fuse panel area - You will have to get to this from under the dash on the back side (Drivers side sitting in vehicle).
There is obviously also a major connection at the engine computer itself. The ECU is located under the hood on the drivers side of the vehicle next to the fender.
There may be other major connections on the harness itself that do not run through computers, but I would start w/ the connection to the ECU and the connection to the fuse panel.
Disconnect the connections and firmly reconnect them again. Do this one at a time and attempt to restart the vehicle each time so you can attempt to narrow down the issue. This can help temporarily clean a possible dirty/corroded contact of a bad connection. If the issue is found, then you will want to disconnect the problem connection and clean all contacts in that connection thoroughly.
If it is not any of those things, it could be the engine control computer. I have had a bad computer in a car before. It turned out that a capacator went out and the whole thing failed causing a no start condition. I tested EVERYTHING on the car first, and finally took a chance buying the ECU and it fixed the issue. This was on a 1990 mittsubishi eclipse, those computers were not designed as well as the modern computers, so it is less likely that is your issue, but you cannot completely rule the possibility out.
Like also mentioned. These things have major issues when air gets in the fuel system. Try bleading the air out of the fuel system and starting from scratch (there should be a procedure for this in your manual, you will have to pump and prime the fuel from under the hood). If this works, even temporarily, it shows there is an air leak in the system. These Jeeps have a pulling type fuel system. The fuel is pulled (under vacuum) at the engine. It sucks all the way back to the tank. Most cars for comparison use a pump in the tank and push the fuel to the engine. The problem with pulling is if there are any small pin hole leaks it will suck air into the system instead of squirting fuel out like the fuel systems that are pressurized from the tank. The air in the system can cause the CRD engine to not start also.
Also, it has been said that the fuel heater circuit has issues on the CRD liberty and cna short and cause problems, not sure what codes this might throw. I am not sure if this short can ruin a computer, etc or not, but you would definatley want to try all possibilities before replacing the computer since if a issue caused the computer to fail it would happen to the new one also.
Hopefully you will have some things to try now. Good luck.
- Mark