99 dodge cummins showing code p1689 and cuts out at about 1600 rpm under any load where do i start

 

1689 is the companion code...means you have another code in another module...scan it with a better scan tool...check lift pump pressure, check voltage at the injection pump....if the second scan shows a 0216 code you need an injection pump...if you have good pressure and have good voltage at the pump...then most likly you need an injeciton pump

 

Not exactly right. As far as I know - P1693 is the companion code.

P1689 is - No Communication Between ECM and Injection Pump Module Data link circuit failure between ECM and fuel injection pump. Low power, engine derated, or engine stops.

Get a can of Electronic Parts cleaner. Disconnect the connector for the Injector Pump and clean out the contacts.
Use a small needle nose to PUSH the contacts into the connector. Use OBDII scanner or disconnect negative battery cable to reset code.


How are you checking for codes?

What is your fuel pressure?

 

checking with ob2 scanner dont know pressure gauge not in yet problem is intermittant one day its fine the next its there

 

evil is right i looked at the number wrong i guess

you can also check the voltage at plug on the back of the pump, i dont recall which pin number it is off the top of my head tho

if its not the voltage or the pressure, then probally going to be the injection pump

 

well i think we may have found the problem ground cable end on the main battery was broke replaced it and so far so goood