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Error code 1689 - dead truck - no lift pump - 8v on coil side of fuel sys relay


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I was out of town and I pulled onto road and the truckstalled. The day before it was loaking but drove fine.

Got Error code 1689 (ECM Comm failure)

Noticed no Fuel pres. Installed new Lift pump and newfuel filter... No fix

Friends shop looked at it and run 12v to Inf Pump pin#7 andGrnd to #6(?). Truck ran for 30min. ECM failure!? ECM replaced butneeded programmed.

Dealership tried to program but continous failures (notenough power to ECM).

1 week later no one could figure it out so I had it towedhome.

Won't start, no fuel pressure and lift pump does not turnon.

No power to VP44 pin#7, constant 12V on Blue with red tracer(Lift Pump feed). There is 12V to the (2) red/white wires to ECM.

Replaced the fuel system relay but only see 8V at the oneside of the relay (coil side). Relay does not switch.

Found that ground from ECM/VP44 wire harness was showing 20ohms. I repaired a the ground connection to the passenger sidebattery. Now showing 9 ohms at ECM plug and VP44 plug.

I read "bluechip diesel's" diagnostic page. Madegood sense but I could not make heads or tails of my lack of power.

Is there anyone who can make sense of this mess? Truck isdead and life sucks riding the motorcycle in the rain.

Feel free to email me as well grunthmc@gmail.com

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I shall. Thanks.The VP44 was not pumping fuel to 1 or 3 but it was pumping to 5 (when I hotwired the #6 and #7 pins on the VP.I think that the problem is two fold (VP and ECM). The ECM needs to be flashed since it is new out of the box. Once I have a new VP installed I will have the dealer program the ECM and hope that the ECM is bad so that it can be replaced.

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  • 4 weeks later...

The relay was not plugged into the correct spot. Before I took the truck to the dealership for a new ECM (the 2nd time) we were trouble shooting the electrical issues and the relay was put into the wrong spot. Once the new ECM was installed I got the 1689 code again. I tore the wire harness apart from the ECM to the inj pump. Everything was solid! That is when I focused on the relay (more so on the wire from the ECM to the relay and back to the inj pump). That is when I noticed that the relay was not in the socket!:stuned:relay installed, injectors bled and the truck started! I have noticed that it is less sluggish since I installed the BlueChip inj pump and a new ECM. Either the ECM or the old inj pump was dieing. Life is good now that I am back on the road! Thanks for the suggestions! Too bad the ECM was actually the problem. I will look to sell the truck next year and upgrade. Maybe someone will want a "project" truck!?

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