i just bought a 2006 ram 2500. I got it cheap because the last owner washed under the hood and now it won't start. I did just a little diag and found that i cannot communicate with the ecm using my smarty. the theft light is flashing and it cranks but doesn't fire. i read that the fan clutch could cause a no start but i could not find whether it was a no crank or a crank no start. any good suggestions.
thanks

 

I'm kind of going through the same thing on my 05 right now. Haven't figured out the issue. I heard that if that theft light is flashing while it is cranking that it is the skim module not reading your key. Since it started after a wash i would check all the connections make sure there is no corrosion. That's where i would start. If not try a new skim module or get the computer re-flashed. I'm not sure why your smarty won't communicate though. It may be a bigger issue than i am thinking, but my 05 is trying the same stuff right now and I'm fighting with the dealership to fix it.

 

Remove, clean and re-install ALL ground connections at the batteries, on the engine block and body.

 

ok so i cleaned the grounds and was tinkering with the truck this after noon. cleaning the grounds made no difference but then i checked the fuses and found #28 missing powers the ecm the abs and some other stuff. put in a new fuse and now the security light proves out like my 2004 but it still cranks and won't start and i still can't check for codes with my smarty and the check engine light now flickers. the guy i got it from said he had replaced the ecm thinking that it was bad. said he bought a used peice and sent it to florida to have a guy program the vin in it. sorry for the long winded posts but i am just hoping somebody has had this trouble and can shed some light on the subject.

 

I had the same issue, twice. It turned out to be a bad "wireless control module" not recognizing the security key (this module has been updated eight times since '06 for this issue!). However, if the previous owner sent the ECM out to some unknown, that may not be helping either. It is probably best that you seek out a good Dodge dealer. You have issues beyond what we deal with on these boards. Each of these modules must be programmed to communicate with each other. You cannot do that. A good do-it-yourselfer knows when to say "when"!

 

The secret code is most likely not transfered into the PCM. The PCM will need to be put into programing mode so secret keycode can be transfered. A starscan or starmobile will need to be used. You will need the SKIMM code in order to transfer code. Code can only be obtained through Chrysler dealership and programed into pcm using their starscan or starmobile.

 

I just came across this on tech connect but since I cannot scan the modules on your truck and check for any codes I cannot be sure one way or the other exactly what your problem is. This is just a guess on my part but may be worth the time to check it out. As stated below remove the #6 fuse if vehicle starts then you have a bad fan clutch.

You might want to call a dealership and have them run your vin for any recalls that may apply to your truck. Such as Customer Satisfaction Notification F15
Reprogram Wireless Control Module The software programmed into the Wireless Control Module (WCM) on about 22,300 vehicles may prevent the vehicle from starting under certain conditions.

K70679999
Vehicle Issue No Start, Unable to communicate with ECM and possibly other modules => Replace the electronically controlled viscous drive fan clutch;Important information There are reports that on some vehicles with the above noted problem that the TIPM is unable to communicate properly. For this reason the TIPM is replaced prior to fully diagnosing the root cause of the problem. This generally results in a bigger problem. If the ECM is also replaced neither replacement module can be programmed until one or the other is programmed. This puts the technician in a loop unless one of the original modules is available. Please stress to technicians that most problems are not caused by multiple module failures and are not corrected by multiple module replacement. If multiple KEY modules such as the TIPM and the ECM/PCM are replaced simultaneously retain the original modules even if an internal defect has been identified until the vehicle has been fixed. A possible No Start condition on 06 Ram trucks with Cummins Diesel engines can be caused by an internal failure of the electronically controlled viscous drive fan clutch. The fan clutch has a battery fed duty cycle solenoid and a speed sense circuit that uses a 5 volt supply. The 5 volt supply comes from the Diesel Engine Control Module (ECM). An internal failure of the clutch allows the battery feed to back feed into the 5 volt feed. This pulls the ECMs 5 volt up to battery voltage. When the problem is present everything within the Cummins ECU that is powered off the 5 volt power supply shuts down. This includes network communication. If the problem appears when the engine is running the vehicle should continue to run. If the problem is present when the engine is off the engine will not start. In addition there is no communication possible with the ECM. This usually leads the technician to incorrectly assume the ECM has failed and should be replaced. Unless the root cause of the problem is identified any replacement ECM will produce the exact same results. If the fan is disconnected the ECM communication / no start problem disappears. No ECU damage has been reported. As a result of the ECM being not responsive and sensor reference voltage being high, several DTCs will likely be present. A very quick check to determine if the fan drive has shorted the K688 18 BR (5 volt feed) to battery voltage is to go the Temperature/Pressure- Intake Sensor on the air box next to the right battery. Back probe the brown wire in cavity 3. The voltage should be 5 volts with the key on but if its 12+ volts the fan drive has likely failed. This circuit is common with the fan drive but this is a much easier access point. If the voltage is high (12+) at the K668 circuit you can disconnect the electronically controlled viscous drive fan clutch 6 way connector at the lower left side of the engine or a much easier approach is to pull the number 6 fuse. Communication with the ECM should be restored and the vehicle should start. This test should be done prior to any assumption that the ECM is faulty.
System or Component No Start;Customer Concern (No DTCs),DTC / Error Message;ECU,Totally Integrated Power Module (TIPM);Yes - Continuously
Recommendation Replace the electronically controlled viscous drive fan clutch

 

got it figured out found the ground wire that goes diretly from the pcm to the battery was broken inside the casing.

 

2006 Ram 2500 w/5.9 same problem.Started up ,check engine light came on , ran O.K.. Shut it down and would not restart. Let sit for about 3/4 hour and it restarted. This time while driving it home warning light for trans Temp came on and ran bad.Pulled over shut it down and wouldn,t restart.Has towed home, scanned and had codes U0100,no communication w/ECM PCM ,P128 TCM Power circuit open, C230 ABS codes U0100 ,C2202 vin mismatch, C2206 . I figured all codes because No communications.I cleaned all the grounds , checked wires , check con. on all wires.Still no start. I am a GM Tech for over 40 years and consider myself to be pretty good at electrical problems but I was getting no place. Went to my near by Dodge Dealer and talked to tech there that I deal with.We kinda help each other.Figued he might have had this problem,no such luck.He looked it up on their Web site but nothing.He looked up code P128 and nothing special, just check grounds.It also had the other codes associated with it.I came home and tried searching on the Web and came up with Big Iron70 post and tried it.Pulled #6 fuse and it started right up. THANKSSSS.