Cel code help........
 

Trucks been throwing the 1689 code. I started to test the truck to see how often it throws the cel. 1689 every time it hits 2500 rpm's

It will cut the power for a few seconds EVERY time it hits 2500ish rpms, it only happens at 2500rpm's. why would it be doing it at a specific rpm? I thought for a while it was only doing it under hard acceleration but its cutting out at 2500??????

Any ideas???

Any one have any ideas? Tested the truck some more and it will also throw the code while revving the engine in neutral, so its not specific to driving under a load, it will throw the code everytime it hits 2500rpms, under load or in neutral.

That is code for vp44 not communicating with ECM.

It has a new vp44 as well as a new lift pump, so i have a hard time believing its the vp44

Well the trucks at the shop now, ill let you guys know what they find out.

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Mechanic says they tested everything and the Ecu is shot, So i bought a new Ecu, and they will be programming it and installing it tomorrow, we shall see if this was the problem........

was it the ecm?

It was the vp44.