Is it posible for a Ford dealer to test the GEM before replacing it? Or is it just a process of elimination?

 

The GEM itself isn't tested, but circuits going in and out are, as well as certain functions within the GEM using output state control.

But there is nothing we have that bench-tests the GEM itself.

Following the pinpoint tests in the manual usually give a good diagnosis.

 

is there an acronym decode list?

lately feel lost.. know others must be too

GEM, IPR, HPOP, etc,etc..

Sam

 

I have seen the GEM refered here as the General Equipment Module and also something else that I can't remember. Sorry, but can't help on the others.

 

IPR = Injection pressure regulator
HPOP = High Pressure Oil Pump
ICP = Injection control pressure
FICM = Fuel Injection Control Module
PCM = Power Control Module
TCM = Transmission Control Module

These are probably the most common, but there are hundreds more.

 

GEM is "Generic Electronic Module".

The 2001 service manual shows the module communication network as including:

The module communication network components — Super Duty Series F-250, F-350, F-450, F-550
l overhead trip computer (OTC) (optional)
l electronic crash sensor (ECS) module
l parking aid module (optional)
l generic electronic module (GEM)
l 4-wheel anti-lock brake (4WABS) control module (optional)
l rear anti-lock brake control module
l powertrain control module (PCM)
l auxiliary powertrain control module (APCM) (optional)

So, I think there's a way to communicate with it, but it takes the big fancy-schmancy Ford diagnostic setup to "talk" to it.

Furthermore, it appears pin 7 on the DLC connector goes to the GEM.

"² PINPOINT TEST D: THE GENERIC ELECTRONIC MODULE (GEM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOL (Index)"

PINPOINT TEST D: THE GENERIC ELECTRONIC MODULE (GEM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOL
² D1: CHECK THE GEM C240A FOR DAMAGE
² D2: CHECK CIRCUIT 70 (LB/WH) BETWEEN THE DLC C227 AND THE GEM C240A FOR AN OPEN
² D3: CHECK FOR CORRECT GEM OPERATION

D2 CHECK CIRCUIT 70 (LB/WH) BETWEEN THE DLC C227 AND THE GEM C240A FOR AN OPEN


1

Measure the resistance between the GEM C240a pin 25, circuit 70 (LB/WH), harness side and the DLC C227 pin 7, circuit 70 (LB/WH), harness side.

l Is the resistance less than 5 ohms?

è Yes

Go to «D3».

è No

REPAIR the circuit between the DLC C227 and the GEM C240a. CARRY OUT the DATA LINK DIAGNOSTICS test.