The ever popular P1689

[Brooks]

As my first post, thanks for all you do for the rest of us...I appreciate you all more than you know.

 
I’m going through the step by step for this code and have run into a snag at step 5. Looking for confirmation with someone else before I start cutting wires. By these results I’m guessing a problem with both my white and black wires between the FPCM and the ECM and I should replace both. (Ironically both these wires have a weird little twist coming out of the FPCM)
 

FYI. Just finished the W-T ground mod. Waiting on a circuit breaker to do the positive side. 

If anyone could confirm my suspicions, i would greatly appreciate it. 

 

 

5. Ensure ignition is off and FPCM harness connector and ECMharness connector are still disconnected. Using DVOM, measure resistance of White wire between terminal No. 2 on FPCMharness connector and terminal No. 13 on ECM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open or high resistance in White wire between FPCM and ECM.

6. Ensure ignition is off and FPCM harness connector and ECMharness connector are still disconnected. Using DVOM, measure resistance between ground and terminal No. 2 (White wire) on FPCM connector. If resistance is 5 ohms or greater, go to next step. If resistance is less than 5 ohms, repair short to ground in White wire between FPCM and ECM. 
7. Ensure ignition is off and FPCM harness connector and ECMharness connector are still disconnected. Using DVOM, measure resistance of Black wire between terminal No. 1 on FPCMharness connector and terminal No. 23 on ECM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open or high resistance in Black wire between FPCM and ECM.

8. Ensure ignition is off and FPCM harness connector and ECMharness connector are still disconnected. Using DVOM, measure resistance between ground and terminal No. 1 (Black wire) on FPCM harness connector. If resistance is 5 ohms or greater, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If resistance is less than 5 ohms, repair short to ground in Black wire between FPCM and ECM.

 

Step 5 I’m showing 0.1 ohms resistance (Continuity)

Step 6 I’m showing an Open Loop 

Step 7 0.0 ohms (continuity)

Step 8 open loop. 

 

 

Edited April 16, 2020 by Brooks
I spelled in instead of I’m and included a picture.

[Haggar]

Double check your measurements, but I am seeing what you are saying.

 

It looks like chrysler expected you to see some continuity from the data link wires to ground, not an open circuit.

 

Did you measure it from terminal 6 or body ground?  You may want to vary where you ground to see if you get any response.... (reason I say this,  anywhere you see Sxxx connection is a splice.  the wiring harness maker did  not use the best method to make those splices)

 

GL

Hag

 

 

[Brooks]

Hi Haggar, thanks for the response. I took my readings from the drivers battery ground. I’ll try a few others to see if I can get a different result. 

[Haggar]

Brooks,

Definitely recheck those using the black /tan wire connecting terminals 6 at the pump and 30 at the ECM as your ground.  If you get a different reading than the open circuit you got during your initial test, then you can be sure that there is an issue in one of the two spices shown.

 

You could do a quick test of the black/tan connecting 6 and 30  to the battery ground.  That should be continuous with a real low resistance.  If it is open or super high resistance  it points to a splice issue.

 

GL

 

Hag

Edited April 17, 2020 by Haggar

[Brooks]

I appreciate your assistance, after double checking the readings. I don’t really have a stable reading. 
It varies from 0.0 to 0.5.  Up to 1.5 ohms on pin 30 vs ground at one point. 
but no open loop. 

[Haggar]

Brooks,

 

If you have both connectors loose, and you are checking from one of the ground pins to ground, the resistance should be steady and nearly zero.....  (you need both loose, so you are not also seeing resistance through the circuitry of the modules) 1.5ohm resistance in the grounding could be a HUGE problem.

 

I stole this snip from IBMobile, but it will help you with the visualization of the splices.... notice the wires just lay together.  there is no mechanical fastening of wire to wire.  These splices can add resistance.  S168 is probably the same way...  his are very clean, but if oxidation has begun to grow in these areas, ghost systemic losses will appear.