obd2 computer drop off.

kb61751 · **Posted:** Tue Jul 03, 2007 1:17 pm

What if anything can be done to keep the computer alive to keep reporting back to the scangage? It does work for about a max of 50 minutes at times, with no problem, why can't it be on for ever?

Joe Romas · **Posted:** Tue Jul 03, 2007 1:52 pm

Nothing short of DC reengineering the computers on our CRD's :shock:

msilbernagel · **Posted:** Tue Jul 03, 2007 2:01 pm

It was so bad that at one point the Feds threatened (or did?) a recall because the OBDII interface was so non-compliant. In the case of the Liberty, there seems to be multiple 'masters' responding where the design called for one (DCX was 'creative'). While their equipment seems to handle it, the aftermarket stuff struggles because it isn't standard and isn't documented well.

These are my recollections from a conversation with the folks who make the scanner I have.

If you can find one that doesn't have the problem, I'd hang on to it.

Mark

kb61751 wrote:

What if anything can be done to keep the computer alive to keep reporting back to the scangage? It does work for about a max of 50 minutes at times, with no problem, why can't it be on for ever?

chadhargis · **Posted:** Tue Jul 03, 2007 3:15 pm

The ECU in the Liberty CRD is a Bosch unit. The guy at InMotion said it's one heck of a good ECU, and only recently was it "cracked" so it could be tuned.

kb61751 · **Posted:** Tue Jul 03, 2007 3:58 pm

The other thought I have is since there are two masters, would there not be two obd2 diag ports some where? One on the DC computer and on on the Bosch? Hook up the scangage to the one that does not go to sleep.

Joe Romas · **Posted:** Tue Jul 03, 2007 4:15 pm

kb61751 wrote:

The other thought I have is since there are two masters, would there not be two obd2 diag ports some where? One on the DC computer and on on the Bosch? Hook up the scangage to the one that does not go to sleep.

No, there are two masters on the SAME buss :!:

Hense the problems :idea:

kb61751 · **Posted:** Tue Jul 03, 2007 7:39 pm

Yes, but one goes to sleep.

retmil46 · **Posted:** Wed Jul 04, 2007 12:04 pm

kb61751 wrote:

Yes, but one goes to sleep.

Problem is, they take turns as far as who's driving and who's sleeping.

Didn't Mopar64 or someone say that in '08 or later, they were coming out with a new model TCM and/or ECM that would finally resolve this problem, such that they would be back to just having one full-time master module? Could be the ultimate resolution to this would be a swapout to the new generation TCM.

RabidRdKill · **Posted:** Wed Jul 04, 2007 3:42 pm

retmil46 wrote:

Could be the ultimate resolution to this would be a swapout to the new generation TCM.

The problem the Liberty CRDs have is the cobbled together vehicle communication achitecture. The CAN based Bosch PCM has some 'glue' hardware and software added to it to talk to the remaining J1850 modules in the vehicle and meet US OBDII specs.

Since the new 08 CRDs are based off the 07 Nitro it is safe to assume it will have the same 'modern' CAN architecture that the Nitro CRD has so it would have a CAN TCM that wouldn't work with our vehicles. Also the Nitro in the CRD application over in Europe has Mercedes 5-speed transmission and it would have different control needs than our 545RFEs.

Joe Romas · **Posted:** Wed Jul 04, 2007 3:52 pm

This site says that all 08 and newer US vehicles will be required to use CAN :shock:

We're left in the dark :oops:

http://www.nology.com/caninfo.htm

obd2 computer drop off.

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