Interesting OPDA findings

Maybe, but first I'd try a full PCM reset first. If your alignment is in the neighborhood, it will work fine.
Is that done by disconnecting the battery? I did disconnect the battery during the time I reinstalled the OPDA.
I'm not getting any codes, or check engine light. Have test drove it, running the engine up to the rev limiter with no limp mode.
The relearn is unnecessary then?
 
Is that done by disconnecting the battery? I did disconnect the battery during the time I reinstalled the OPDA.
I'm not getting any codes, or check engine light. Have test drove it, running the engine up to the rev limiter with no limp mode.
The relearn is unnecessary then?
Full reset instructions here: https://wranglertjforum.com/threads/any-benefit-to-resetting-pcm.15762/post-254238

The details of what is stored in adaptive memory is found in the FSM. I do it whenever I change any PCM sensors, but it's for you to decide.
 
Don't be confused, the PCM has many learned functions that can not be erased with just a battery disconnect. A battery disconnect does nothing more than a scan tool does when you hit the erase button.

The symptoms you describe in relation to your CPS not working when it is cold is likely because your CPS to crank is out of sync. We have found that the CPS timing between a cold engine and warn engine can vary as much as 1.5 degrees of cam timing. So as you engine warns you CPS to crank sync may very well change enough for the PCM to accept the CPS signal as good.
Great informative stuff!! But I have 1 Question about a timing chain with 160000 plus miles on it. That is, is it worth while to replace timing chain and gears, to stabilize these things. Would not slack cause constant miss reads either on the plus side or negative side depending on wear. May God Bless;DL
 
Surely recreating the drb3 functionality isn't beyond the capability of someone... I feel like a tuner manufacturer or @Wranglerfix could do it with some windows software and a pre existing USB to odb2 cable. Am I crazy?
 
Chrysler has an emulator for the DRB, it does most stuff other than some really low level operations and it runs on a PC. It's part of their new diagnostic tool set.

Guessing it's still not cost effective for a hobby user? That's really what I'm after. Would be nice not to have to depend on the dealer to activate my SKIM or relearn the cam sensor, if/when the time comes.
 
Great informative stuff!! But I have 1 Question about a timing chain with 160000 plus miles on it. That is, is it worth while to replace timing chain and gears, to stabilize these things. Would not slack cause constant miss reads either on the plus side or negative side depending on wear. May God Bless;DL
The timing chain will cause scatter in the readings. It's easy to check with a breaker bar on the crankshaft. Just rotate it and feel for play in the chain. If there is enough play to change the readings you will easily feel it.
 
What's cost effective? It's a subscription service from Chrysler as far as I know. Most dealerships don't have a working DRB anymore, they just use the emulator or at least my local dealership does.

inexpensive enough that I wouldn't regret buying it if I only ended up using it twice. I could see a one time $500. A subscription wouldn't make sense unless it could be bought a month at a time for $100 or less, but I wouldn't guess they offer subscriptions to just any Tom, Dick, or Harry trying to keep his TJ running.
 
They'll take your money whatever name you want to give them. I think the service is for independent shops as well as dealerships. A three day pass is $36 or something in that range but you might need a wiTech device. There might be clones floating around. $500 is used snap-on range and I've heard they can do most of what you described but I don't know about which models do what. I think somebody mentioned a snap-on unit could read CVI values from the TCM and that's pretty low level stuff.
 
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It should just be a matter of writing some code. There isn't much in a USB-to-OBD2 dongle, just the main ELM327 (or equivalent) chip with a few support chips to talk to the OBD busses (J1850, ISO, CAN). The hardware is simple, it's just various flavors of serial data.

The problem is knowing the exact protocol for telling the PCM to start a relearn for a specific sensor. I haven't found that level of detail published anywhere, and I suppose Chrysler likes it that way.
 
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They'll take your money whatever name you want to give them. I think the service is for independent shops as well as dealerships. A three day pass is $36 or something in that range but you might need a wiTech device. There might be clones floating around. $500 is used snap-on range and I've heard they can do most of what you described but I don't know about which models do what. I think somebody mentioned a snap-on unit could read CVI values from the TCM and that's pretty low level stuff.
That price point is not completely out of line but I would want something that could do it all.
 
I really like my Jeep so that's what I did. The funny part is I just replaced my OPDA and I managed to get it in spec so I didn't even need the DRB. I tweaked it a few degrees just to get it spot on but sometimes that's how things work out.
You got the witech device and the subscription? Or the DRB?
 
It should just be a matter of writing some code.
There are some open source projects that use Chrysler J1850 and ELM327 adapters but only work on mini vans. I've written software to read the bus but I'm not writing packets on my Jeep. Replacement black boxes are getting expensive and I'm not that talented.

You got the witech device and the subscription? Or the DRB?
DRB3, it was great to get the security code from the dealership and walk out that door for the last time. Nobody needs it, that's for sure but it's fun to have.
 
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Yeah, for Chrysler mini vans, because there are so many soccer moms who wrench on their own vehicles. :p

I don't think I'm up to that gamble with my PCM either. But I wonder if WranglerFix has a fix for this in their boxes.
 
Yeah, for Chrysler mini vans, because there are so many soccer moms who wrench on their own vehicles. :p

I don't think I'm up to that gamble with my PCM either. But I wonder if WranglerFix has a fix for this in their boxes.
Our replacement pcms are probably from some minivan, which even if that's the case my POS is check in the road and has been so for 1.5yr so far thanks to whatever magic Mark conjured!
 
But I wonder if WranglerFix has a fix for this in their boxes.
The cam sensor needs to be adjusted so the pulse is in sync with the crank. I don't really know what you mean by a fix? It's not like this is a problem that needs to be resolved, it's just an adjustment that should be made with every sensor replacement.