ECM receiving too much voltage ? 2002 Dodge Ram

[Takingbreak21]

Hello, thanks for letting me join. my first thread....
2002 dodge ram 2500 5.9L
It wont go past 40 miles per hour on the hiway... Once in a blue Moon, it behaves and will go up to 75., but acts up later....my mechanic told me I needed a new ECM, I ordered one online, but still has same issues. I sent it back to see if they can figure out why its happening......they told me the ECC is receiving more than 18 voltage and that ECC cannot withstand voltage over 17v... I probably have to go buy a scan tool maybe? not sure how where to begin to make sure ECC is not receiving more than 17v.....thanks

 

[OC455]

Might get a quicker response if you posted this in the 2nd/3rd Gen forum.

 

[Takingbreak21]

Thanks for that tip....will do.

 

[pacofortacos]

Do you have a voltmeter? What is the voltage at the battery when running?

 

[Takingbreak21]

no volt meter....I'll have to go buy one ......then i;ll check what voltage of battery is at running.

 

[pacofortacos]

Advance auto or autozone might have one and could check your battery voltage when running.

If you are getting 17 volts at the ECM, you should have 17 volts at the battery. Which means that your charging system is over charging, if that's happening then comes the fun on finding that problem.
Since you already tried another ECM, I doubt it is that - most likely a wire or alternator issue.