Archived Truck Down!

[troutscout]

Hey everyone. I started driving my truck this morning and it developed a small hesitation/rpm drop. As i drove down the road the truck started accelerating and decelerating on its own with little or no throttle response. The truck would run at idle speed and then accelerate for different lengths of time and then idle down. Once i got it back on the road to my house, i stopped trying to use the pedal and let it limp home on its own.

Codes:1693-DTC detected in ECM or PCM,

0118-ECT sensor voltage to high

0523-oil pressure voltage to high

0238-MAP sensor voltage to high

0121- Accelerator pedal position sensor does not agree with idle validation signal

0563- charging system voltage high,1475-Aux. 5 voltoutput to high,0343-????,where do i start,or what do i replace to fix this

 

[BigPapa]

Need to tell us what truck you have.



If you go to the user control panel and put your truck info in your signature it will post it whenever you post and you won't have to do it but once.

 

[troutscout]

That info would probably help! The truck is a 2001 2500 automatic

 

[LNaugle]

sounds like the computer on the firewall... . the built in regulator has shorted or full fielding...

 

[JLandry]

Test the voltage output from the alternator, and if that checks out fine, then you'll need to test the regulated 5V sensor supply output of the ECM. If the output from the ECM is exceeding specifications, it will require a replacement (rebuilt) ECM.

If you have the skill to troubleshoot the electrical system (i. e. : you know how to use a multimeter), then I can post detailed instructions on what to do. Just let me know.

Regards,

John L.

 

[troutscout]

Thanks guys. Yes i can trouble shoot it if i know what to look for. Please post the detailed instructions. I had to go out of town for the weekend, so it will be monday afternoon before i can work on it

 

[JLandry]

Thanks guys. Yes i can trouble shoot it if i know what to look for. Please post the detailed instructions. I had to go out of town for the weekend, so it will be monday afternoon before i can work on it

OK, the simplest thing to start checking would be the internal 5v sensor power supply of the ECM.



First, with the ignition off, verify the batteries are fully charged by checking for ~12v at the battery terminals. If necessary, charge the batteries.



Next, with the ignition still off, check the voltage at pins 48 and 50 of the ECM's 50-pin connector and the negative terminal of a battery. There's no need to remove the connector from the ECM to do this as you can "back probe" (click the link for a picture) the wiring harness connector using paperclips. I'm not a big fan of piercing the insulation of a wire when testing because this creates an entry for moisture which could lead to corrosion in the future. See the attached diagram for pin locations in the ECM connector. Both of these pins are connected 18 ga red wires with a white stripe. This check verifies there's nothing wrong with the power supply wiring leading up to the ECM. Be careful not to short anything out while doing these tests.



Next, turn the ignition on (but don't start the engine) and check the voltage between pins 10 and 11 of the 50-pin ECM connector. Pin 10 should be connected to an 18 ga orange wire and pin 11 should be connected to an 18 ga Black wire with a Lt. Blue stripe. Pin 10 is the +5v sensor supply to the oil pressure and the MAP sensors. Pin 11 is the ground for these circuits. Ideally you should find ~5v DC on this circuit (min of 4. 6v and max of 6v). If you find in excess of 6v, then the voltage regulator inside the ECM has failed and you'll need to replace the ECM.



Please let us know what you find and we'll try to help you troubleshoot further.



Good luck,



John L.

 

[troutscout]

Ok, at the risk of sounding stupid,what i thought was the ECM is not. Where is it located?

 

[JLandry]

Ok, at the risk of sounding stupid,what i thought was the ECM is not. Where is it located?

It's bolted to the driver's side of the engine block below the fuel filter assembly. It may be easier to access it if you unbolt the fuel filter housing from its bracket and swivel it out of the way (no need to disconnect the fuel lines).



It looks like this:



#ad

 

[troutscout]

I have 12. 9 volts at 48 and 50. 4. 99 volts between 10 and 11. Suggestions? Thanks

 

[troutscout]

I did not mention it earlier but i have a Edge EZ box on the truck(EZD1000). Could that be the issue? Should i remove it?

 

[BigPapa]

That would be the first thing I'd try. Anything's possible.

 

[KRStone]

How does that box ground? Through the box or through a harness with a ring terminal to the frame? Could be a bad ground.

 

[JLandry]

I have 12. 9 volts at 48 and 50. 4. 99 volts between 10 and 11. Suggestions? Thanks

Repeat all measurements, but this time with engine running. It's possible the alternator is over-charging with the engine running which would send excessive voltage to the ECM that it can't properly regulate down to 5v for the sensors.



If possible while taking the measurements, try wiggling and moving the wiring harness in the area around the ECM to see if there might be an intermittent short. This is a long-shot, but it can't hurt to try.



If your measurements still come up normal with the engine running, clear all the trouble codes using a code scanner and let us know if they come back and if the engine is still misbehaving.



This problem could internal to the ECM, and if that's the case, will require a replacement.



Best regards,



John L.

 

[JLandry]

How does that box ground?

The ECM is grounded through the wiring harness. Pins 30 and 49 of the ECM connector are the grounds.



John L.

 

[troutscout]

I checked the alternators voltage last night. It was 14. 1 volts.
I did not check it at the ECM while running. If 14 volts is making
It to the ECM, is that to much?

 

[JLandry]

I checked the alternators voltage last night. It was 14. 1 volts.

I did not check it at the ECM while running. If 14 volts is making

It to the ECM, is that to much?

That voltage is fine. You should still try and check the voltage between pins 10 and 11 with the engine running just to rule out any change.



The reason I suggested clearing the trouble codes is to see how quickly they return. Your measurements seem to indicate nothing external to the ECM is wrong, but if the ECM still thinks there's a problem, then the ECM likely has an internal failure.



John L.

 

[troutscout]

I removed the Edge EZ this morning. started the truck and it idled fine. I let it run for a few minutes and decided to go to the parts store to see if i could get the codes cleared and get a new fuel filter. I made it to the store and they said that they could not do it. My brother has a scan tool but i will have to wait until tomorrow to use his. When i left the store the truck started doing the same thing. Once i made it back home, barely, i checked and had 2. 5 volts reading across pins 10 & 11. I guess the ECM is bad. I checked the alternator output and did not detect any increase in voltage output. i watched for a couple of minutes. Next question, where do i get a replacement and how much is it going to cost me this time. I just got the injector pump/supply pump and transmission paid off. Sorry, a little bitter at the moment. Do you think that an increase in voltage from the alternator caused the issue (all of the high voltage codes) or the ECM just failed? I am going to unhook the batteries and remove the plug from the ECM and make sure that there isn't any dirt or corrosion in the plug.
I really appreciate all the help. Thanks again

 

[JLandry]

Next question, where do i get a replacement and how much is it going to cost me this time.

New ECM's for 2nd gen engines are no longer being made, so that's out.



Rebuilt ECM's are available through Cummins or Dodge for $1000 or more and may require a core. They require initial programming AFTER being installed in the vehicle. If on-vehicle programming isn't possible, I believe that Bob Wagner of SmartyPower has the capability to bench program an ECM.



You can buy used ECM's on eBay starting at around $300, but that's a somewhat risky proposition because there's no assurance they won't have defects. If you do buy a used ECM, make sure it's from a truck with the EXACT same year and configuration as yours (Fed vs. Calf. , Manual vs. Auto, etc. ).



There are also "refurbished" ECM's available on eBay and elsewhere on the Internet, but they can also be hit or miss because some of these shops seemingly only clean up (and sometimes not even that) then resell without bothering to test or repair.



You might check with Automotive Electronics Solutions to see what they have or can do for you. STAY AWAY from Auto Computer Exchange in Davie, Florida. Do a search here on the forum and Google if you want to know more about their business practices.

Do you think that an increase in voltage from the alternator caused the issue (all of the high voltage codes) or the ECM just failed?

I'd guess the later, because if you had an overvoltage condition from the alternator, you should've seen specific trouble codes for that.



Good luck,



John L.

 

[troutscout]

I saw that you had mentioned AES in a different thread so i gave them a call. I can send them mine and they can repair it,depending on whats wrong,for $580-$790. I can also purchase a rebuilt unit from them for $895 and not have to wait. Just a little info for folks with the same trouble.