GEM Module Reconfiguration (Computer Flashing)

[ExplorerDMB]

I recently had this topic posted in the modified explorations, but now it is closed down, I wanted to keep this discussion open so I could be updated, as well as me updating others on my progress.

The Goal: Simply, reconfigure/flash my GEM Module (or other modules) so that the computer will read the correct speed.

Why This Way: I do not simply want a little box just sending the correct signal to my speedometer. I want my computer to read correctly as well. I am not much of a wiring-freak, so this will keep me out of trying to wire up a Superlift Tru-Speed or any other module like that. This will be more accurate as well, even though the Tru-Speed can come within plus or minus 1%!

How I'm Getting There: I will be using the Ford NGS and possibly the WDS to do this. These are expensive tools, and aren't exactly your "every-shop-has-it" tool, but we are fortunate to be the best shop in the Richmond,VA area - so we have tools.

What I've Done So Far: With a non-fully updated NGS (with NGS GreenCard), I was able to get into the GEM Module (and other Modules), but it would not return a GEM Protocal or allow me to type in the REV/Mile.

What's Next: We recently updated the NGS and will try again to see if anything can come out of it. If not, I will try with a WDS to possibly update the computer.

Here is the information given from a Ford CD-ROM on how to reconfigure the "inaccurate speedometer":

Ford: 1998-2000 Explorer, Mountaineer, Ranger

Action:

Reprogram the GEM, CTM, or 4WABS Module to match the vehicle attributes. Refer to the following Service Prodecure for details.

Service Procedure:

In the event a 1998-2000 Ranger GEM/CTM/4WABS or a 1998-2000 Explorer/Mountaineer 4WABS/CTM component requires service or replacement, the module(s) must be configured for proper operation using a New Generation Star (NGS) Tester and verision 6.0 Service Function Card. If you do not have verision 6.0 loaded, use the latest version Service Bay Technical System (SBTS) CD to download NGS Service Function Card Version 6.0 software to the green NGS service card for configuring modules. To configure modules, follow these instructions:

1. SELECT: SERVICE BAY FUNCTIONS
2. SELECT: GEM, CTM or ABS
3. For ABS, proceed to Step 4. For GEM or CTM, SELECT: CUSTOMER PREFERENCES
4. SELECT: TIRE SIZE/AXLE RATIO CONFIGURE
a. The NGS Tester will display "DETERMINING MODULE PROTOCOL, PLEASE WAIT"
b. When NGS Tester is ready, press {TRIGGER} to continue.
5. ENTER TIRE SIZE/REVOLUTIONS PER MILE (REV/MILE)

NOTE: THE TIRE SIZE MUST BE ENTERED AS A REV/MILE CALCULATION. REFER TO THE REV/MILE CHART FOR THE CORRECT CALCULATION.

6. ENTER AXLE/TONE RING SIZE

NOTE: 4X2 RANGERS EQUIPPED WITH A 2.5L OR A 3.0L ENGINE HAVE A 7.5" AXLE. 4X4 AND 4.0L RANGERS HAVE AN 8.8" AXLE. ALL EXPLORERS/MOUNTAINEERS HAVE AN 8.8" AXLE. IF THE SPECIFIC AXLE CANNOT BE SELECTED, ENTER THE AXLE TONE RING TOOTH SIZE USING (00102) FOR 7.5" AXLES AND (00108) FOR 8.8" AXLES.

7. ENTER OPTIONS
8. ENTER VEHICLE
9. SELECT: DONE - The NGS Tester will display "MODULE CONFIGURATION COMPLETE."
The module is now properly configured. Press {TRIGGER} to exit
10. Verify with road test

Time: 0.7 HR.
Operation: 992604A



REV/MILE CHART

Tire Size = REV/Mile

P205/75/R14 = 00800
P225/70/R14 = 00794
P235/60/R14 = 00797
P215/75/R15 = 00750
P225/70/R15 = 00761
P235/75/R15 = 00721
P265/75/R15 = 00679
P245/75/R16 = 00681
P255/70/R16 = 00690






Information on the NGS/WDS tool: These tools will soon be useless. The WDS will soon be scrapped, due to Ford and other manufaturers going to laptops and PDAs. All the laptops and PDAs will be able to read from 1996 and on. The WDS and NGS will not read anything passed 2005. It will not even communicate with the PCM/ECM. Our shop will be switching over to laptops and PDAs as soon as local Ford dealerships do. I am almost 19 and I hope to be a huge part of teaching our technicians how to use the PDAs and Laptops! We will also be one of the few shops that do reprogramming/flashing PCMs in our area.



-Drew

 

[410Fortune]

is there a question in there?

I am coming over to use your tools

 

[ExplorerDMB]

is there a question in there?

I am coming over to use your tools

haha no just a lot of information. I am hoping to reprogram my computer soon so my speedo will read correctly. Also, at the shop we are just getting into reprogramming and well - the tech guy said there is a section for tire size and gear ratio configurations. So I want to see what'll happen. Looks like it might be fixed at a touch of a button.

-Drew

 

[ExplorerDMB]

Same results. "Unable to reprogram; GEM Module unconfigurable". Looks like I need a new GEM module that I can program.

-Drew

 

[Katmandu]

If I do a rearend gear change, wouldn't the rear ABS Sensor send the correct signal to the speedometer anyways ??

 

[ExplorerDMB]

You would hope so, but for me and Jeff it did not. In theory you are correct, but you have to remember that the computer uses different things to calculate speed.

-Drew

 

[Katmandu]

...the computer uses different things to calculate speed.

-Drew

What different "thing" does a 98 4x2 Explorer use to calculate speed ??

 

[ExplorerDMB]

Well vehicles in general use different things to calculate speed, transmission shaft speed, ABS Ring, Front ABS Sensors -- you can possibly take your '98 to a dealership and have them recalibrate for the tires/gears. Hopefully you won't run into the same problem I have (a non-configurable GEM).

-Drew

 

[Katmandu]

you can possibly take your '98 to a dealership and have them recalibrate for the tires/gears.
-Drew

What's a "fair" price to pay a Stealership to recalibrate the speedo for a 98 Ex ??

 

[ExplorerDMB]

I believe an hour and half of labor -- around $100+ is my estimate. Call them up and see what they'll say.

-Drew

 

[storlied]

That's rediculous..

 

[Cobraguy]

That's rediculous..

Not when you are writing $10,000 checks for tools. It's a very reasonable fee.

 

[imp]

ABS Sensors and Gear Ratio

If I do a rearend gear change, wouldn't the rear ABS Sensor send the correct signal to the speedometer anyways ??

ABS sensors generate their info from the rotation of the vehicle's rear differential ring gear carrier; therefore, only the tires' rolling diameter determine the ABS "count". Different gear ratio changes the driveshaft (and therefore, the pinion gear) speed, so yes, changing rear axle ratio will NOT affect speedometer/odometer calibration.

On vehicles using driveshaft speed to generate a signal (like old EEC-IV system) from what was called VSS- "Vehicle Speed Sensor", YES, axle gear ratio affects speedometer indication. imp

 

[Cobraguy]

ABS sensors generate their info from the rotation of the vehicle's rear differential ring gear carrier; therefore, only the tires' rolling diameter determine the ABS "count". Different gear ratio changes the driveshaft (and therefore, the pinion gear) speed, so yes, changing rear axle ratio will NOT affect speedometer/odometer calibration.

On vehicles using driveshaft speed to generate a signal (like old EEC-IV system) from what was called VSS- "Vehicle Speed Sensor", YES, axle gear ratio affects speedometer indication. imp

That is correct. However, a tire size change will require a speedo calibration. And on certain years, that is done in the ABS module. My 1999 for example receives the VSS signal (for the speedo and all required systems) from the ABS module. It receives signals from all three ABS sensors. As long as ONE is working, the ABS module converts it to a usable VSS signal and outputs it to the necessary systems.

 

[nordictom]

Speedo Calibration

I know this is an old thread, but I just purchased my first Explorer, 1998 XLT 4dr. , 4x4, 4.0 sohc.
It came with 33" tires & a Superlift lift kit. I know by now, everyone has probably figured out how to re-calibrate the speedo on their Explorer's.......

My questions is, Has anyone changed the speedmeter with the "Auto Inginuity" software? I have access to it, & just thought it might be able to do this, instead of making a trip to the dealer.

Thanks
NT