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Limp Mode Codes P2149,P0202,P0203,P0205, P0208

Mousie2004

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Need help once again truck is a Chevy 2004.5 LLY 2500 HD 66,000 miles. I had this same problem last year truck would shut down completely and I would have to pump the primer to get to run like it was out of fuel never actually run in a limp mode either run or not. I replaced the fuel hoses, new filter and primer pump it didn't help same problem. Then it just went away and run ok till Saturday. Engine light came on and truck shut down. I pumped the primer and it started run about a mile and shut down would not start anymore we pulled it back to the shop and I run a scan and got codes P2149,P0202,P0203,P0205,
P0208. Did some research and replaced the no.2 and no.7 injector connector with new GM connectors they seemed the most prevalent for failure. I removed the other 6 and did the ice pick thing. Cleared the codes drove 5 miles no problem. Started down the road this morning it went in limp mode went back to shop cleared the codes now is running ok I'm sure it is going to leave me stranded on the side of the road. One strange thing when it want start fuel gage is on empty and light on but I have a full tank. I have already replaced the stepper motors in the instrument cluster. Thanks
 

btfarm

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There was also a problem with the harness getting a short where is crosses over the alternator from rub through causing limp mode. I had that issue with my LLY and found out it was common.
 

Mousie2004

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There was also a problem with the harness getting a short where is crosses over the alternator from rub through causing limp mode. I had that issue with my LLY and found out it was common.
I'll take any suggestions at this point. I will run the wiring around the alternator and see what I can find. Just crazy that when its runs its just like when it was new. Thanks
 

Mousie2004

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I'll take any suggestions at this point. I will run the wiring around the alternator and see what I can find. Just crazy that when its runs its just like when it was new. Thanks
I peeled the wiring harness back from the EDU unit up past the alternator to the driver side engine and could not find any issues. I have ordered new injector connectors for the remaining 6 just hoping maybe it could be one of them and wait for a failure.
 

Rockabillyrat

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Most of the time I find a shorted wire when I have those codes. Don't just focus by the IDM. Check every inch of the harness. I've seen them short all over the place. EGR, power steering, supply lines ect... Leave it run and move the harness around and see if it shorts. A small spray bottle with water is helpful too.

Connectors are also a problem because the terminals are small and open up. I always check the remaining 6 when I do the TSB. A pin drag test is a great test if you have the tools. I made the investment in a terminal kit. You would be surprised at the amount of trucks I fix simply adjusting a few terminals.

Dont overlook a shorted injector. They are broken up into two batches that share a power source. If one shorts out it will take down the other 3 on that batch. I've had them short only when the truck was hot so if it acts up, ohm them right away.

Also I have yet to put a IDM in a duramax for any reason. They don't fail, but it could happen.
 

Mousie2004

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Don't have pin test kit one would be nice. I will try the spray bottle tomorrow and continue to peel back the remaining harness.
 

THEFERMANATOR

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Also I have yet to put a IDM in a duramax for any reason. They don't fail, but it could happen.
I've seen several 01's, a few 02's, and a couple of LLY's lose FICM's. Peperridge was one of them. But they all gave the death code when they went.

And like I put in your PM, this problem is most likely a short. The fuel gauge going to E when it won't start is a dead giveaway of a data coms issue. Typically a loss of j1850 will take down the gauges, but not stop it from running since the vats signal is on a dedicated j1850 line that only runs between the ECM and BCM. It's been awhile since I had an LLY with the ficm harness short, so I can't remember if the FICM going down effects data coms or ECM output's like j1850 since the FICM is on a different J1939 line between the ECM, FICM, & TCM(not sure about the gpcm on an LLY).
 
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