Looking for any kind of help/advice on getting my 99 Ram 3500 5.9 out of limp mode. I purchased this truck 6 months ago and finally getting around to getting the CEL off and the truck out of limp mode. After clearing old codes i would start the truck and the rpms would begin to go up and at about 500 rpms the needle would drop and CEL come on. Truck would then be in limp mode and run smooth. The code was a P0341. I started with a cam sensor replacement. Made no difference. I ohmed out the wires from the CMP connector to the ECM connector pins and all 3 wires were ok. I cleaned the connectors and cleaned battery cable ends and all grounds. I started the truck and it threw the same P0341 code. I moved the wiring harness around that runs up the timing cover area and things changed, the tach was working then engine shut off and would not restart with code p1689. I cleaned VP elec connector and cleared codes then restarted, the tach was working but a little erratic and engine was doing a little dipping and revving by itself then tach dropped to 0. Cel came on. Tach went back to 800 then back to 0. Checked codes and had p0341 and p1690 this time. Moved the same wires around a bit i was messing with previously and now im back to the P0341 code only. Im stumped at this point and wondering a few things.....

-does the crank sensor have to do with this issue even though a crank code is not set?
-does this sound like a bad ECM?
-so far it sounds like a harness issue

 

Hey man my truck is doing the same thing!! If you figured anything out on this could you please give me a call!? 541-410-3633 thanks, John.

 

Any hall type sensor is virtually impossible to diagnose without an oscilloscope. If you have good power and ground with the sensor plugged in the next step would be to test the signal with an oscilloscope at the ecm connector. This will verify wiring to the ecm in one single step. I would also recommend graphing the power and ground circuits at the sensor with the oscilloscope while the failure is occurring. This will lead you in the direction of the failure! Any testing that doesn't involve an oscilloscope is a guessing game at best for this type of failure.
It might be worth while to measure voltage drop at the ecm and pcm power and grounds while this is occurring! If you don't find any issues when looking with the scope you'll move further into sensor ring issues or faulty computers.
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so I bought this truck and now get the cam sensor p0341 cel. I can clear the code and it comes back on anywhere from 30 to 160 miles. I haven't gotten around to changing sensor yet but that will be my next move. All the plugs looked good, but still need to pullback wire sheath and check wires.
Anyone find their issue. I'm hoping it's not the cam gear like a few people said.