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Discussion Starter · #1 ·
I preface the following with a little background. I am a Communications Electronic Technician in the Navy and have the been troubleshooting electrical problems for 13 years. Outside of the navy I have built/repaired multiple vehicle, but the is my first Diesel.



Ok, so it's an 04.5 2500 auto, for a while now it has been popping codes that I think might be related to the MAP sensor. I just need a back up to my theory. I just replaced the batteries tonight as the past couple days it's been extremely hard to start.... turn key until wts light is off, take the key to the starting position and it would fall on it's face and roll over very slow until it caught. So, one could assume the codes could have been a voltage issue... but I don't. When the truck is running, I would see 14.44 at each battery, shut down it was 12.1 leading me to believe the battery's (Maintenance free :doh:) were bad and I had lost a ton of ampreage retention. The 14.44Vdc would in my mind provide the required voltage to the ECU and subsequently the sensors.

Anyway, ON TO THE CODES!

P0341 CAMSHAFT POSITION SENSOR "A" CIRCUIT RANGE/PERFORMANCE
P0652 SENSOR REFERENCE VOLTAGE "B" CIRCUIT LOW
P0193 RAIL PRESSURE SENSOR HIGH
One code that I normally get with these is the boost sensor reference high, however for whatever reason it was not present this time. Hence my question of WTH is going on with my truck!
I have attached the portion of the factory service manual with the line diagram, which would also lead me to believe that a new ECU is in my future.


Hopefully, you fine gentlemen will tell me otherwise. So, honestly, thank you in advance. Slainte'
 

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Discussion Starter · #2 ·
Anyone have anything???? Just got the same ones along with the MAP sensor barometric pressure fault. They clear, but I'm 100% sure that it'll come back.

Thanks in advance.
 

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The Dodge Cummins ECU has an internal 5.0v regulated voltage pwr circuit that supplies the reference voltage for the sensors.

often see the 5v line shorted out, sometimes intermittently, to other wiring or chassis due to pinched or worn thru cheap insulation used on the Dodge wiring. very poor wire management, harness over insulation protection and too short wires/harnesses causing strain against points. must be at least 50 ft of 5v ref. wiring in these with all the branches, some branches feed several sensors.

the reference ground which is originated in the ECU often develops shorts to chassis and engine points causing noise in the sensor reference circuits in the ECM processor. garbage in, dog feces out.

the split paralleled dual battery system with one batt fed by the alternator and other batt measured for charge V. by ECU leads to lots of electrical problems in these. Look for cable failures, chassis ground failures, lots of corrosion points. Corrosion =s V. drop. V. drop on main pwr in to an ECU processor caused both temporary and permanent failures and false readings. ECUs live in the world of micro seconds. Lots of ground loops in these. The paralleling crossover + cable is a known weak failure point.

peel the insulation back on the batt cables, all connectors for corrosion. replace if Big C., NO new ends.

do you have the full shop electrical manual?

ECUs seldom fail on these except from dufus jump starts or fried OV alternators. Sometimes a programmer or Dodge shop ECU factory programmer will toaster one.
The inputs/outputs are well protected internally by protection devices. Programming lockups can tie up the internal write prog.
try key on 3 times and see if it reads out any codes in the odometer window.
DONE indicates end of code test.

if you're getting a normal dash display from the ECU indicating it past POST power up self test, it's 99% certain it's good to go.
 

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You dont happen to have a banks module on the truck do you? I would throw cam and crank codes with the 5 volt ref code every couple weeks. I removed the banks and the problems never returned. If not, i would check over the harness and check for rubs. If the harness is good id replace the cam sensor and see what happens. If the sensors bad and ir sharea the 5 vref and signal ground with other sensors it could be causing the problem

Sent From Commando
 

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Hey guys could not help but notice the post, i am having some electrical problems my self and it sounds like you guys have some electrical know how, my odometer reads out no fuse when i start it up, but throws no code, and my radio, cruise control, and upper console are not working? any thoughts, and i checked all the fuses everything is in place and working, unless there is another fuse panel besides the one under the hood by the driver side battery
 

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Discussion Starter · #6 ·
Sorry to dredge an old topic but I figured it could help someone else out down the road. The issues that I was having above came back over and over again. So I started the Easter egg hunt of replacing sensors. Took the better part of 6 months or so to finally be able to call out the "problem sensor". It ended up being the CAM position sensor. A little trick make it easier to replace. Unmount the computer from the driveside of the block, then there is TONS of room! I hope this helps someone in the future! Cheers!

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down by the a/c compressor bracket some wire loom was missing from factory, the insulation gets rubbed off a 5 volt supply wire intermittenyly shorting to ground causing your type problems
 

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Discussion Starter · #8 ·
Thanks for the input, this was most definitely the CPS. All of the sensors in the pic above share Ground and 5V reference. By one of them going bad, it was intermittently giving symptoms of a shorted 5V.

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Thanks for the input, this was most definitely the CPS. All of the sensors in the pic above share Ground and 5V reference. By one of them going bad, it was intermittently giving symptoms of a shorted 5V.

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So your was the cam posistion sensor correct? i'm having a issue on a 2010 P0652 with associated ETC flashing, and my fuel rail pressure is always reading 25k even with the engine not running :shock: and at idle and 2k rpm. I changed the cam posistion sensor with not luck and have been all over the harness looking for a short with no luck, and have taken the voltage at all associated sensors in the 5v ref voltage setup and they all pass, might look at the ac bracket as mentioned above
 

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Discussion Starter · #10 ·
Not sure on that as the schematic i used is from an 03-07 FSM. There may be differences. I would try to find a '10 wiring schematic and see where traces lead.

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