DTC P1690 what exactly is causing it?

[LawDawgSHPD]

Lately I've only been driving my truck maybe 2 times a week. Since it turned cold it's been difficult to start if it sits overnight unless it's plugged in. However here in NC the temperature only dropped below 30 for maybe 2 weeks this year so I didn't see the need to plug it in. I usually bump the starter the first time to let the FASS run for 30 seconds but then I still have to crank it for like 15 - 20 seconds before it finally starts with lots of gray white smoke & rough idle for about 30 seconds then it smooths out & runs fine. All gauges work fine & check engine light hasn't come on but I checked the codes anyway & the only one was P1690 fuel injection pump CKT sensor does not agree with ECM CKP sensor. Called a Cummins tech I know who works at the local Dodge dealership & all he could tell me was to replace the Crank position sensor. I trust his word 99.9% of the time but wanted to hear what anyone else did to fix this problem. Truck is a 98.5 24v.

 

[Bob4x4]

There are a number of things that can cause this code,fuel delivery,bad wiring,bad injection pump,failing sensors

 

[GReed]

My 2002 was getting the 1690 code. Eventually, it got the 0216. It would start fine, but blow white smoke until it warmed up. Only did it when temp was 30 deg or lower. Was still under warranty. Dealer replaced VP44. Still did it. I replaced cam position sensor. No more problem. I believe your year has both, cam position sensor and crank sensor. I would start with the crank sensor. If that does not fix it , then replace the cam sensor. If the dealer had replaced my cam sensor, maybe the VP44 would have lived.