Hi Guys,

Hill decent would not engage.

Bear with me, I have read several threads on the transfer case Hi Low switch as mine was not working. I did the whole strip down on the console, including all the riveting! The switch was dead but I didn't want to spend the money yet on the OEM switch so I tricked the system with a manual install and have a switch on the console now.

Push the transfer lever into Low, hit the switch, press the HDC switch, put into gear and voila, the HDC works perfect.

In addition, I am using Autel ODBII diagnostic and it shows the transfer case in High Range and then Low Range correctly when you toggle the switch.

So what! I hear you say?

Using the Autel, I am looking at the Automatic Transmission diagnostics and it says "low" detected from the transmission High Low sensor. This is odd to me as it changes to "High" when I throw my new Low Range manual switch into low range.

This is an issue for me as this transmission setting triggers different mappings based on the transmission recognizing low or high range according to the RAVE.

The Autel also threw me a code on the AT. 27 High/Low Range Sensing.

Seems like the signals are backwards but switching my switch wires make now sense obviously. Is there a reset needed of the AT ECU?

Thanks in advance.

 

Is the hill descent light supposed to stop blinking when you switch into low range? Mine continues to blink and there's a chime going off constantly.

 

Yes, once the ECU detects Low Range AND you put it in gear, the HDC will stop blinking.

The Transfer Box High Low Switch was not working and therefore the HDC blinking would not stop before my repair. I took it out. Check for continuity, no dice, cut the wires, put them together, carefully checked again and bingo HDC light went solid. I put the old switch back into the box as a plug, then wired up a toggle switch to the console.

Works fine, although I found the other issue mentioned above after I bought a diagnostics tool.

Incidentally, my transfer box neutral chime warning switch does not work either and at $100 CDN a pop, not worth it right now. Same type of switch I believe?

Going to try to trick the computer this morning by setting switches. turning off (disconnecting battery maybe) reset switch. Turn back on. I'll let you know.

 

OK can't trick it, didn't expect so.

Could be a problem with the Autel programming?

RAVE is limited and I'm a mechanical engineer not an electrical one lol.

Does anyone know what the AT switch/sensor looks like, could it be reversed?

Anyone else see this in their diagnostic tools?

Thanks for any insight.

 

RAVE Manual states this:

High range
Unique lock-up maps, similar to the shift maps, are incorporated in the economy and sport modes for all forward gears.
Engagement and disengagement of the lock-up clutch is dependent on throttle position and engine speed.

Low range
To enhance off road control, particularly when manoeuvring at low speeds, torque converter lock-up does not occur
when there is any degree of throttle opening. When the throttle is closed above a preset engine speed, the lock-up
clutch engages to provide maximum engine braking.

So when in high transfer box, my AT is reading Low therefore would appear to have incorrect mappings.

 

What exactly are you asking that anyone else sees in their diagnostic tools?
I have a Hawkeye. Do you want to know what it says when in the transmission settings, while shifting the cdl?? Did you want live data??
I just checked for transmission codes yesterday, and have none. So my 04 should be functioning correctly.

 

Hi, thanks for responding.

If you could please, I'll try to explain. Nothing to do with the CDL, just the Range.

With the Autel, there are two parts to check.

In the ENGINE diagnostic, the transfer case switch i.e. moving from High to Low, changes from High Range to Low Range as expected.

In the AT (automatic transmission) diagnostic, it returns "Low" from the High Low sensor when the transfer case is in High Range, and "High" when in Low Range.

So basically my transmission thinks the transfer case is in low range when it is actually in High Range and vice versa. Thus my concern about the mappings.

I know it is a little confusing, but I understand that the transmission need to know when the transfer case is switched to Low Range from High Range to match the gearing and lock up torque characteristics, but my vehicle is reporting opposite settings.

 

So just switch mine between high and low, and see how the Hawkeye reads it?
Correctly, or vice versa like yours. Is that what you need to know?

 

If your maps are now inverted, high to low, wouldn't a test drive prove it? As you would have noticeable engine braking while in high range?
Im at work now, but I'll check with the Hawkeye this afternoon and post back.

 

Hi n Sixpak,

Thanks again, I have been flicking the switch during driving, no noticeable difference in engine performance and braking etc. It does throw the code "High Low Range Sensing" if I do this, presumably due to speed sensing and what not.

I would add that I noticed that on the AT diagnostic, it also misreads my gear switch positioning, I am now wondering if the programming from Autel is reading the AT ECU correctly. The vehicle seems to be working very well. Gear positioning is reading correct on the instrument panel.

Who knows?