"Range Change Not Available" Fault

[socalrovershop]

what code in what module are you getting this fault in? you have to look up the codes in the transferbox module engine control module and transmission control module in order to be pointed in the right direction

 

[kwlr3]

I printed the section of the workshop manual called "Four Wheel Drive Systems - Four Wheel Drive Systems; Testing and Diagnosis". Page 2 lists the DTC codes, Possible causes, and Actions. Keep in mind that this code is happening while I'm driving. If the battery was bad I think I would get the code on start up. Also, the code seems to happen more frequently when it's hot. Resistance in wiring goes up with heat, makes me think there is a bad ground somewhere.

Where is the ground connection for the battery? (behind the engine fuse block?)
Where is the ground connection for the wiring harness that supplies the ground to the t-case control module?

 

[socalrovershop]

what code are you getting this off of? you need to be looking up codes in the transfer box mdoule or transmission module

 

[kwlr3]

I'm using an OBDII code reader and the DTC code is P06562 and I'm looking that up on the DTC index for Four-Wheel Drive System Diagnosis and Testing. When I start up, there are no codes on the OBDII nor is there a message on the dash. When I start driving and the chime goes off, I get the message on the dash and P0562 SYSTEM VOLTAGE LOW shows up on the code reader.

How can read codes from just one module? I thought all of the DTC codes were transmitted to the OBDII port via the CAN BUS regardless of where the code originated.

 

[jimbiram]

I would guess the alternator as well. I've had mine replaced...some of the systems are more sensitive to voltage than others....

 

[ryan-in-oregon]

With the IDS/T4 or Faultmate you read the codes through the individual control units. There is a "system wide" scan function but that really just gives you an idea of what faults you have in each system. In order to see the specific info you scan each module. Generally speaking if you have voltage issues one of the first faults will be with the HDC. I wouldn't necassarily rule out the alternator but have you had it checked? I would also check grounds and power feeds to that module.

 

[socalrovershop]

your generic scanner is only reading the engine control module. you need to find out what your transfer box module is logging. thats why GOOD scanners are pricey.

 

[kwlr3]

I gave up and took it to the Dealer. Here is the verdict. I was told I have two problems, the first low cost one is that the Integrated Transfer Case Control module needs to be reprogramed. It is either sensing excess wear in the transfer case or due to the multiple times I disconnected the battery and did a memory purge, it has lost it's initial program parameters. The mechanic thinks it will likely be OK with just a reprogram but warned that if the transfer case (the clutch plates) are too worn, I'll need a new t-case. Second issue, Transmission Fault Reduced Traction is due to worn clutch plates in the rear differential. Apparently, the rear diff is controlled by a different module and it can not be re-calibrated and that when the self check is performed the locking control motor drives up against the end of it's range. I had long ago suspected that something was amiss with the rear locking diff because whenever I switch to rock crawl mode, I haven't seen the little orange lock light up on the 4x4 system screen. That's been missing for about 2 years and 30,000 miles.

Looks like about a $4000.00 repair bill.

 

[socalrovershop]

ahhhh so i was some what right. thats way too much money for a reflash that takes about 5 min and no labor is involved and the fix for the rear is a new locking motor wich takes no longer than an hour or two to do . the locking diff is a bulletin issue .

 

[kwlr3]

Re-flash did not work. A clogged battery vent tube (happened back in May but I thought I cleaned it all up) caused the connectors to the t-case module to corrode. The terminals for the box stuck in the connector when the mechanic removed the box. In addition there was obvious acid stains between the t-case box and the engine control box. With broken terminals, I need a new Integrated Transfer Case Control Module.

The battery was the start of all of the "low range not available" problems. But, not because it was dead (not quite two years old) but because the vent tube was clogged. I replaced that battery and cleaned the battery compartment with lots of water and baking soda and re-routed the vent tube. I knew to not let water get into the black plastic box at the rear of the battery compartment but evidently, the damage was already done.