Have a quick question that is way out of my experience base.

A friend has a P0A90-13 code that I found a pin-point test for (2018 Ford Expedition with ELSD).

The pin point process led us/him to a faulty ELSD control module (same as the DCM-rear?). I am not sure where that control module is located. Is it actually on top of the rear differential? If so, what needs to be done for replacement? He says it is not accessible if that is where it is (he is in a different location from me, and he has big hands, lol)?

Many thanks!

 

I believe it is an ECM (electronic control module) that is supposed to be mounted on top of the differential.. Under the circumstances it might be a good idea to get a second opinion because it could be the module, the connections or even the wiring. Maybe the pin point test might direct you to the problem, but as you know we would like to be sure before buying anything, what do you think?

 

I still wish this forum had a "LIKE" button!

Thanks Hanky - I agree.

I did find these:

https://diag.net/msg/mafpgyp5etujxy1scfur09b0u4

https://f01.justanswer.com/drhorsefi...150a_TEST2.pdf

 

P0A90:13 Drive Motor "A" Performance: Circuit Open This DTC occurs when DCMR detects a open circuit signal.

For DTC P0A90:13, GO to D5

D5 CHECK THE DIFFERENTIAL PUMP MOTOR FOR AN OPEN

Disconnect Hydraulic Pump Motor C3830 (4 pin connector).

Ignition OFF. Disconnect Hydraulic Pump Motor C3830 . Measure:
Hydraulic pump motor, component side, pin 1 - Positive Lead
Hydraulic pump motor, component side, pin 2 - Negative Lead

Is the resistance greater than 10 ohms? It was greater than 10 Ohm.

Yes: INSTALL a new ELSD HCU . REFER to: (205-02B Rear Drive Axle/Differential - Vehicles With: Ford 9.75 Inch Ring Gear, Removal and Installation).


Seems way too simple!

Just to document:
The ELSD control module part number was Jl1A-4C016-D or Jl1A-4C016-F
The Hydraulic Pump motor part number is Jl1A-4C180-B

 

As we all know, those simple little jobs that should take only a 1/2 hour to an hour are the ones that wind up taking 4-5 hours if lucky.
Thanks for the info, lots of good reading there. If it wasn't for the location difference and because the gent has big hands, I just know you would be more than willing to climb under there and get the readings while he read the directions to you , huh ? lol

We all have the scars to show for it . I agree with your decision !