700 mile report...

Tire rub fixed (added spacers) and oil leaked fixed (lucky was only a hose to the turbo), but now Check Engine Light is on (It's running fine). I misplaced my engine code reader, so went down to AutoZone and had them read it.

P1670: EF Feedback Signal Not Detected

Is there anything I can do to disgnose this, or should I take 45 minutes away (Costs me $50 in taxi fares) to my 7.3 Mechanic? (Powerstroke Diesel Solutions, Paramount, CA)

The mechanic from the dealer I bought the rig from in Salt Lake City told me that I need to have someone with a better scanner, run a diagnostic and see which injector is having the issue. From there... I am lost. I did some research about PCM and IDM issue..

I found this info on a quick search on Google... It does not mention injectors.

DTC P1668 and P1670 indicates that a communication error has occurred between the PCM and the IDM.

Possible causes:
Open fuse, IDM relay, Open or shorted IDM enable circuit, IDM powering circuit, PCM

Check for other codes. Key on, engine off.

l Perform KOEO On-Demand Self Test and retrieve Continuous DTCs.
If DTC P1298 is also present, REPLACE the IDM.

Planning my first big trip this next weekend to Trona Pinnacles out in the desert and want to make sure I am not going to be stranded.

 

Check the connector for the IDM for moisture. Then check the wire harness and plug for the PCM for damage and moisture. They are right next to each other if you pull the wheel well liner. Check my axle swap thread for a photo of the wiring/plugs with the wheel well liner out. PCM and IDM are within 12 inches of each other...

 

At my mechanic now. Hopefully nothing too expensive. We haven’t had any moisture here (SoCal)

 

Update: Took to a Powerstroke shop and he came back with nothing. Said that he cleaned some electrical connections and the connections to the Hydra chip. This last weekend, I went on my first big journey, was awesome and MARGE ran great. No issues, no loss of power. HOWEVER, when I started in the morning, loaded with gear the started turned and turned and did not start. I stopped and tried again and started up no issues, then the light came back on. Same code.

About 200 miles into the drive the CEL turned off for awhile and then came back on with another ignition start up. This time it started up just fine.

Curious if a voltage issue could cause this code? One battery is about a year old and the other is unknown.

 

If you are running stock sticks (injectors), then disconnect your batteries (both) and unplug your Hydra where it meets the PCM.

Drive it like that for a while. If the code never comes back, then there you go. If the code DOES come back, then suspect PCM.

 

I would check for a bent pin in the PCM. I had one of those and it caused a CEL.