Ecm ?

[TBusclas]

Brief history, about a year ago started truck and it would not accelerate normally. RPMs would build slowly as long as you eased into the throttle up to a certain point and then start to build quickly. Was able to get it home and pull the trouble code which I don't remember at the minute but I replaced the TPS under the battery, cleared the code and thing were good again. Some time after that started having other strange problems, wipers at times would not work unless full on, close the door and wipers would come on and run couple cycles and a couple other strange electrical gremlins with dash lights, gauges etc. that would occur momentarily and go away, nothing that ever stays long enough to trouble shoot. Also during this time twice had the same original symptoms as above but only unplugged the TPS, cleared the codes and was off and running again. Week before last truck died again, same as above. Tried unplugging and resetting as I had previously done, but have a new wrinkle, codes are not clearing. I hit the clear button on the scanner and it says codes are gone but when I run scan immediately again without starting truck the codes are still there,tried another scanner and still the same. The truck is currently with my mechanic who has better diagnostic capabilities than I. All connections and ground relating to the ECM and the system have been checked. I can't remember his exact words and terms but he is getting some strange wayward signals that should not be showing up. We are both leaning toward the ECM being bad but he is still checking a few things as he is not the type to throw parts at something especially with the price of the ECM. Anybody have any thoughts or suggestions. Thanks!

 

[cerberusiam]

Couple things to check: AC clutch activation wire can scuff and partial short on things it is anchored to, vistronic fan can short and completely shut truck down, battery cables corrode internally causing bad connections. All of those plus bad diode(s) or in the alternator or a bad battery will throw a series of dirty signals into the system.

 

[MJWenrich]

If you bought your truck new, you should have received a letter from RAM that the ECM has extended lifetime coverage on the ECM due to "the software programming of your vehicle's ECM may fail to accurately report diagnostic system information that can result in a failure of certain state mandated inspection and maintenance tests". I received this letter dated Dec. 7, 2010. This may or may not be a consideration but might be something others on the forum would know if it can cause the symptoms you are experiencing.

 

[Bob4x4]

It is not the ac actuator wire (what ever that might be in your book)but 5 volt sensor supply ckt that can wreek havoc since so man ysensor supplies are on the same ckt

 

[Wayne M.]

If you bought your truck new, you should have received a letter from RAM that the ECM has extended lifetime coverage on the ECM due to "the software programming of your vehicle's ECM may fail to accurately report diagnostic system information that can result in a failure of certain state mandated inspection and maintenance tests". I received this letter dated Dec. 7, 2010. This may or may not be a consideration but might be something others on the forum would know if it can cause the symptoms you are experiencing.

I bought my 04.5 new, and never got that letter.
I did have the rubbed out visitronic harness and before and after the harness- P2121 and check engine light with a similar throttle characteristic.
I most recently watched the TPS signal with my scanner, and I had a erratic signal or noise in the TPS at idle so I took the plunge and replaced it. So far so good.
You might have a bad wiper motor causing the wiper issue. Really check the basics. A bad battery can wreak havoc.

 

[TBusclas]

Thanks for all the replies and I want to report back where I am at. Have literally checked every connection and ground on truck, batteries included. We are still coming up with this erratic signal and same driving/throttle response issue. Only thing left is is the ECM, anyone have any further thoughts and lastly, any recommendations as to source for ECM. I hate spending money needlessly but also will spend more dollars up front to make sure it is right first time. I don't want have to look back when half way across country when I have installed an inferior or substandard part. This will always cost you more in long run than doing it right the first time. That being said good source for an ECM? Thanks all!

 

[cerberusiam]

Good source? New OE ECM from dealer or Cummins, about $2k. Will need programmed and that requires either a dealer or a shop with a tool to program the ECU and a subscription to Tech Authority to get the correct flash. The last I heard was ~$2600 thru a dealer.

There are a couple ECM reman places out there that have varying results. Expect send it back twice to get it all working correctly, then be ecstatic if the get it in one. Generally around $800 for a reman ECU plus shipping if you have problems.

Did you carefully examine every battery cable end to make sure there was no corrosion internally? Unless you have replaced the cables it is a good bet the cable from driver side battery to starter is bad under the sheath and\or ground cable on the passenger battery is bad under the sheath and\or the cross over cable is bad internally. Either of those locations having less than great cables will cause weird electrical stuff to happen. The main power feed to the ECU is also highly suspect as it will corrode internally also and you cannot see it.

With the age of the truck all the batter cables and power feeds plus the FCM connections are suspect. Replacing all of cables, or just cutting the ends off and doing terminals, plus the FCM and fuse box is still cheaper than an ECU.

 

[Prairie Dog]

You will likely see nothing in regards to corrosion at the grounds unless you unscrew them and reinstall.
Cannot over emphasize how important clean grounds are!

 

[TBusclas]

Sorry for the long delay but after two surgeries and some other life happens just wanted to let all who chimed in final outcome. We removed and reattached every ground, connection on the truck seemed like two or three times. Finally went back to batteries cables for what ever reason. Had cleaned and took off and checked several times. Finally started replacing ends at batteries one at a time and checking results as we went. Lo and behold on the ground on the passenger side when replaced all bad signals went away. Dissected end and never did see anything that was suspect but after replacement everything fine and have had no problems since. Darn I hate these kind of gremlins. Thanks all !!!!

 

[seafish]

Sorry for the long delay but after two surgeries and some other life happens just wanted to let all who chimed in final outcome. We removed and reattached every ground, connection on the truck seemed like two or three times. Finally went back to batteries cables for what ever reason. Had cleaned and took off and checked several times. Finally started replacing ends at batteries one at a time and checking results as we went. Lo and behold on the ground on the passenger side when replaced all bad signals went away. Dissected end and never did see anything that was suspect but after replacement everything fine and have had no problems since. Darn I hate these kind of gremlins. Thanks all !!!!

SORRY to hear about other problems, but THANKS for the update. That was very smart of you to check results as you went along!!!