CEL: No RPM Gauge and..

SuperDave4x4

SuperDave4x4

popcorn playa
Joined
Apr 23, 2006
Messages
3,416
Riding down the road yesterday my CEL came on and my RPM gauge stopped working, but when I came to a stop the engine acted as if I blipped the throttle 4 times in a row. I was completely stopped and no where near the go pedal. I pulled over and shut the truck off and let it sit for 2 or 3 minutes the cranked it back up. The CEL stayed on, but my RPM gauge started working again however once I got down the road a few miles the gauge stopped again.
When I went to leave work yesterday there was no CEL and my guage worked fine, but this morning the light came back on and no RPMs. Also I haven't had any irratic idling any more, it only did that the one time.

Everything else works fine.

I dont have the Torque APP since I got and iPhone so I have no way of checking the codes at the moment.

Any ideas on what it could be? If the light is still on when I leave for work today I can stop by Advance Autoparts...(as much as I dont want to)
 
$1 says your ECM just took a schidt. Seen that happen many a times. My old truck did the same thing to me 100K ago and it did it again just recently just after Rick sold it. It will be on it's 3rd ECM soon. Possible it could be a sensor....but I doubt it. List the codes you are getting. Probably a bunch of low voltage and high voltage codes for a whole gob of sensors.
 
Oh please dont tell me that!

Where does one get a new ECM?


EDIT: Is one ECM better than another? A reman from RockAuto is 243 PLUS a 90 dollar core charge.
 
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I got mine from DodgeECU.com or some crap. Make sure they get the VIN and mileage programmed correctly. They missed my VIN and since it didn't match the ABS module, it threw a CEL every time until I got it corrected.

Not saying that IS your issue....just looks that way. :(
 
4x4dually said:
I got mine from DodgeECU.com or some crap. Make sure they get the VIN and mileage programmed correctly. They missed my VIN and since it didn't match the ABS module, it threw a CEL every time until I got it corrected.

Not saying that IS your issue....just looks that way. :(
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http://www.DodgeECU.net it looks like.

I'm just getting my ducks in a row incase it is the ECM. It sucks because I'm leaving for Canada Saturday morning and wont be back till the following week, so I'd like to get this figured out before I leave.
 
Find a like truck with the same tranny and swap the ECM first. Make dang sure that is your problem. Swap shouldn't take but 30 minutes or so to do it, test it, and swap back. Pretty expensive item to not be 100% certain.
 
Oh I'm not ordering anything until I get the codes read.

Since Torque isnt available for iPhone, what is a good engine diagnostic App that can read DTC?
 
Can you cycle the key four times, leaving it on the last time and get them to flash on the dash?

Vatozone will read them for free.
 
In on this to see the results. Another tech I work with has the same symptoms.
 
4x4dually said:
Can you cycle the key four times, leaving it on the last time and get them to flash on the dash?

Vatozone will read them for free.
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Mines a 99 and apparently that does work. :( AThe 2000 and 2001 I beleive are the ones that can do that trick.

zfaylor said:
In on this to see the results. Another tech I work with has the same symptoms.
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Glad to see I can help! LOL

4x4dually said:
Reading from back when mine did it. I'd guess you may have a few of the same codes.

http://www.competitiondiesel.com/forums/showthread.php?t=21732&highlight=ECM
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I just went out to the truck and tried to read the codes with a reader we have at work. When initially plugged in nothing came up, but it had and option for enhanced Chrysler/Jeep codes so I chosen that option, under that there was Engine and Transmission, I chose Engine and it said it could not link to the computer and to check if the Ignition was 'on'. I tried it 3 more times, but only got the same message each time. I backed out and chose Transmission and it linked and read the transmission just fine.

The CEL was not on at the time. I'm going to read it when ever the CEL comes on again.
 
SuperDave4x4 said:
Mines a 99 and apparently that does work. :( AThe 2000 and 2001 I beleive are the ones that can do that trick.



Glad to see I can help! LOL



I just went out to the truck and tried to read the codes with a reader we have at work. When initially plugged in nothing came up, but it had and option for enhanced Chrysler/Jeep codes so I chosen that option, under that there was Engine and Transmission, I chose Engine and it said it could not link to the computer and to check if the Ignition was 'on'. I tried it 3 more times, but only got the same message each time. I backed out and chose Transmission and it linked and read the transmission just fine.

The CEL was not on at the time. I'm going to read it when ever the CEL comes on again.
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LOL thanks for being my unwilling test mule!
 
Sounds like the ECM is too fried to even send diag codes. :( That sucks. Find a SnapOn Modis or some decent scanner and try it.
 
4x4dually said:
Sounds like the ECM is too fried to even send diag codes. :( That sucks. Find a SnapOn Modis or some decent scanner and try it.
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Let me clarify.

It did read for codes when I initially plugged the "Innova 1403" into the port, but no codes were found. However it has an enhaced code section which gives me two options under that setting, Engine and Transmission. I chose engine and it never would communicate, BUT (that's a big but) I looked through the manual on the scan tool and it only covers diesels from 1992-95. Don't ask me why.

Im going to run the truck at lunch today and carry the scan tool with me so I can plug it in when the CEL comes back on.
 
I hope it is just a crank sensor. So the tool only reads '92-'95? Did they even have ECM's back then? LOL What the hell.
 
When mine went out the first thing to go was the thermostat gauge, then a month or so later the tach would cut out also lose power to lift pump explaining the rough idle/ lack of power. Took an ecm off another truck and all is good. Mine had a dent in it so i'll try to keep this one from riding on the frame!!

Sent from my EVO using Tapatalk 2
 
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