seer1

There are two wires running to the sensor on the transfer case. If there is a resistance of 1, it tells the ECU you are in 2wd. A resistance of 65 ohms tells the ECU it is in 4wd. I have two 33 ohm resistors in the wires along with a toggle. When I toggle it on, the ESP/ABS goes off, but it doesn't behave like it's in 4lo. The throttle is way too responsive allowing the tires to break traction way too easily. Usually at the worst possible moment. I've been told a resistance of 12.5 ohm tells the ECU it is in 4lo, but I haven't had the chance to check it out yet.

The Falshpaq Crawl tune makes the whole 4lo thing irrelevant. It makes the throttle control perfect. There is no more unwanted rev as you are wobbling back and forth over boulders. There is a great deal of forgiveness in the shinny pedal. You still want the 65 ohm feed so the traction control etc turns off though.

KenB1010

Thank You for the information. Do you happen to know if a resistance of 65 ohms and/or 12.5 ohms will allow the use of the E-disco on the Rubicon? I would like to have ESP/ABS stay on in 4Hi due to the Snow/Ice driving that I do in the winter time.

seer1

That I don't, but would like to. I don't even know if the 12.5 thing is actually true yet. My axle upgrade is well into its third week (projected 3 days to do it) and I won't get to playing with the electricity stuff until I finally finish this.

Patxi12

I have a JK Rubicon with atlas 4sp and 60 Dynatrac Prorocks.
I solved my problem using a two throw manual switch, two inputs and one output to the ECU. In one position there are two 33 ohms in series for a 66 ohm , and in the second one 220 ohms, so there is no flasihing light in the instrument panel.
In normal operation I use the 220 ohms, and for low operation i use the 66 ohm.
It works very well.
Regards

seer1

That's some great information! Any way of getting the wiring diagram on that?

Patxi12

Seer1

My computer skills are limited, so I do not know how to put here a diagram. Also excuse my english, I live in Monterrey Mexico.

But let me tell you what a I did .

I got the Atlas adapter for my 4SP TC and it did not work, then I installed the sugested 33+33 ohms in the line, and it worked in 4low, but I had a flashing light in my intrument panel, with a DTC .

I took out the sensor (swicht ) from my original TC and I found that there are 4 different resistance values, as you push the sensor simulating 2H, 4H, N, and 4L, in 2H shows 220 ohms, and in 4L shows 62 ohms.

So I simulated this situation with a manual two throw switch, and two resistances one is 33+33 = 66 ohms, and the second I think is 210 instead of 220 ohms.

Then I took the two line that goes from the ECU to the 4sp TC sensor, and from one line I connected in paralell the two resistances, then each one to one of the two inputs of the two throw switch, and from the output of the manual swicht to the other line that goes to the ECU

So now I can select from my manual switch in my dash two positions, one with a resistance equivalent to the 2H (220ohms) and the other to 4L ( 66 ohms), and send this information to the ECU . Nothing to do with the Transfer Case. So when I am in an off road situation I can have the 4L signal to the ECU any time that I want, or 2H without a flashing light .

If you need more information please let me know

KenB1010

Patxi, this is great info. Let me see if I can restate this so that I can build it. You used a 2-position switch. 1 pole of the switch goes thru 66ohms of resistance then to one lead from the original TC wiring. Another pole goes thru 220ohms into the same TC lead. The other side of the switch goes to the second TC lead. In this way you can use the switch to tell the ECU that you are in 2H or 4L.

A few questions:
1. Do you remember what the resistance was in the N or 4h positions?
2. Do you notice any issues with not having N or 4H wired in?
3. I see that you also have a rubicon model. Does your electronic sway bars work in 4H and 4L with your switch setup? Because of the sway bar and the winter driving that I do, I have a need to tell the ECU that I'm in 4H as well as 4L, 2H.
4. Any idea what the ECU does with the N switch info?
5. Have you had any of the throttle control issues in 4L that Seer1 has reported?

Thanks you for sharing your information. This is going to be alot of help to me.

By the way, your english (written) is very good.

From your post and Seer1's it looks like:
2H = 1ohm (Seer1) or 220ohms (Patxi12)
4H = 12.5ohm (Seer1?)
N = ?
4L = 66ohm

KenB1010

The atlas web site says that the 66ohms adjusts the throttle mapping. It sounds like this didn't work in your application.

From Atlas web page:"In essence the Low-range switch tells the computer what mode the transfer case is in. To operate the needed functions on these vehicles, we find the need for only one of the normal four possible mode positions, and that is the “Low-Range” mode. This mode allows the factory lockers (and electric sway bar if equipped) to work on the Rubicon series TJ & JKs. The other necessity is the ESP (ELECTRONIC STABILITY PROGRAM) in the JK series of Jeeps. By installing the Low-Range switch in the JK’s it will automatically turn the ESP to its lowest setting possible. Allowing front digs in low range, tire slippage without engine hesitation or braking feedback. It will also change the fly-by-wire throttle sensitivity to take away the side affects that usually consist of jerky throttle response that occurs as a result of running low range without the Low-Range switch hooked up."

seer1

Oops, I see I wrote it a bit wrong. Two hi is basically a broken circuit. Where you get that 1.0 reading on the meter and usually say bad words because now you have to trace the line. The 12.5 is info I've gathered elsewhere and again haven't had the chance to check it first hand yet. Maybe it's because I had the 2.72 Sahara case, but those two 33 resistors in the line make the 4x lights go on on the dash but didn't do anything as far as changing my throttle. Paxti your writeup makes perfect sense thanks!

Patxi12

Hello Ken :
My answers to your questions are as follows

1.- I do not remember the resistance values for the other positions, but it is very easy to get it, just disconnect the wire from the original transfer sensor, and use a multimeter to measure the resistance in the 2H, 4H, N and 4L positions. But I believe that you will not need it unless you use a rotary switch, with 4 positions with the 4 different resistance values, and you manualy change the switch any time you go to 2H, 4H, N and 4L . The only benefit will be to see the 4Hight light in your instrument panel when you select 4H in the switch, because I believe , and not very sure, that the ECU only has two settings, one for 2H,4H and N and other for 4L .

2.- In 220 ohms position, my JK works well in any T. C. position , remember that this is a manual switch that has nothing to do with the T.C. For street driving, I only use this position.

3.- My electronic sway bars only can be disconnected in the 66 ohms position, not in the 220 ohms position, the same way that the original T.C. works in 4L (62 ohms)and 2H (210 Ohms).

4.- Nope

5.- The electronic throttle control in 2H and 4H has a delay function, to reduce gas consumption, in 4L this delay is eliminated. (Same with the switch )

This modification is working fine for me in offroad aplications only. Because in 66 Ohms position equivalent to be in 4L, you will loss the ESP (ELECTRONIC STABILITY PROGRAM) function, so be aware of this.