P1689 fuel pump code

[1994ch]

I am driving my brothers 01 cummins. Was out running errands and it did not want to start. After a couple of tries of five seconds or so of cranking it finally fired a little and then stumbled to life. The check engine light came on and I got P1689. I don't know much at all about the cummins.

 

[THEFERMANATOR]

P1689 can be a couple of things. Many are because the pump driver on the vp44 died and it lost communications with the ecm. But it can also be set if there is a problem in the fuel pump relay or it's circuit as it powers the vp44. So make sure the fuel pump relay is good and working(swap the relay with another), check the fuse to make sure it is good and clean, but if they check out, then you will probably need to diag the vp44.

 

[1994ch]

When the vp44 dies will it usually have a complete failure? or will it continue to run for a while and cause intermittent problems? The truck is currently running. I will clear the code and see if it comes back (the light stays on but I don't know if the light will go out if the problem goes away) I will also check lift pump operation as well as the relay and connections. Thanks for the input!

 

[ak diesel driver]

A fuel pressure gauge is probably more important on these engines than the 6.5 . No fuel pressure is IP death in short order

 

[1994ch]

Thanks! If I keep the truck very long I will definitely add one. I checked the schrader valve at the pump and it had fuel pressure there at idle. Also the engine light went out this afternoon...........

I think it needs a new set of batteries and I know it needs a new set of battery cables.

 

[THEFERMANATOR]

Think of the vp44 like the ds4. They both use a pump mounted driver that is cooled by the fuel running through it. The primary difference is the vp44 runs at MUCH higher pressure(more than double). But both pumps can run without fuel pressure to them, but only for a short time before damage occurs. Cummins used a carter rotary van pump on the 1st 24 valves and 03 to early 04 common rail engines before they came to there senses, and Dodge yanked the engine mounted pump off and eventually installed one in the tank(for a short while they were using a frame mounted lift pump as an upgrade). I did ALOT of those carter lift pumps back in the day, and subsequently alot of vp44 pumps that got starved for fuel and died from it.

When the pump driver is going, sometimes pouring cool water on it will get it started back up so you can limp it home. I also did quite a few ecm's on the 24 valves for the 98-99 trucks with no starts, or they died during a flash. Try explaining to a customer that his truck he brought in running perfectly fine is now dead as a door nail because you were doing a flash update for a recall, and they now have to wait 4 days for a replacement because they are on star line restriction and can only come from Cummins. And to top it off, the replacements many times had to be flashed as they would come blank, and don't ask how HAPPY a customer gets when the replacement ecm dies during flashing. Oh yes, the good old days of working on the all mighty never breaks Cummins(or at least that's what so many owners of them believed).

 

[1994ch]

So as an update. Had some more trouble with the battery cables, once I cleaned them up a little better, all the problems seemed to go away. Fingers crossed hopefully it was just the voltage dropping down too low on startup.