Archived Truck dies with a P1689 code

[TCluff]

Well, I just bought this truck about a month ago, It is a 99 3/4 ton, quad cab, 4x4, auto, Edge Ez box, 4" straight pipe. Anyways about a week after I got her home the batteries went south, no problem replaced them. Then about a day after that a horrible thing started. You'll accelerate to about 2400 rpm and it is like somebody reaches over and shuts off the key, gauges and everything stays on, but the truck stalls to about 1200 and picks back up, but sometimes it dies and the injection pump info on my scanner(Snap On) reads 0 engine rpm when cranking, fuel temp is like 3226 F, the shutoff solenoid is on and the bat voltage at the pump is 14. 2 volts. When this happens it won't start for a few minute then the info goes back to normal and it will start fine. Engine light comes on and the code has been P1689: no com between injection pump module and ecm. So we sent back to the dealer, and they just changed the lift pump, They gave it back and it does the same thing. I would take it back to them but I live two hours away and work alot, plus they only gave me a 1000 mile warranty, which was up pretty quick. So I started reading posts on this site thanks to a referral by a friend and joined cause I liked what I read. Anyways checked the lift pump pressure, it was about 12psi at idle and 10 at wot. I read to clean all the ground connections and plug ins on the engine, did that. Reset the APPS, still the same thing, removed the EZ box and no change, I was wondering if you guys have ever had this problem and is it going to lead me down the path of pump replacement. Thanks for you time and efforts.

 

[DieselMinded]

Map Sensor maybe??



Seems to get replaced alot when people have simiar problem ??



DM

 

[rkressg]

I had the same code. It cost me an Injection Pump, MAP sensor, and an engine wiring harness to fix. I had a dead short between pins 13, and 23 on the ECM wiring harness which goes to pins 1,2 on the PECM connector on the pump. It took all three of those parts to fix the problem.

-Rich

 

[BushWakr - RIP]

The diagnostic trouble coding list I have indicates:

>>>P1689 = No communication between ECM and injection pump module.

Brief description of DTC = Data link circuit failure between ECM and fuel injection pump. Low power, engine derated, or engine stops.



I hope that helps a bit... .



regards, bob.