DrWagon

Everyone,

Currently troubleshooting some PCM issues. Original tune was replaced with a popular vendor's mail order tune. First iteration of the vendor tune produced a real problem between sensor communication where the CMP and CKP sensors were out of sync rendering the car undrivable.

Vendor asked to check if tune was correctly set up for my Frankenstein configuration. The original problem was fixed after vendor retuned the computers resulting in expected idle and throttle response. Upon the first drive cycle the transmission was clearly not being commanded correctly and seemed stuck in 4th gear (imagine trying to ride uphill on a bicycle in the absolute wrong gear). Tests of manual control using the gear selector while at a stop felt each gear (P-R-N-D-2-1) engaging. Regardless, the car never shifted all the way to 55 mph once moving. I didn't drive faster, but the RPM and speed were expected for my gearing when in 4th.

Went to hook up the scan gauge to check codes and there was no connectivity (first iteration of the vendor's tune version had full OBDII connection). Tried the fancier shop gauge with no improvement as well as my Ultra Gauge. All pins/connectors in each the E38 and T42 computer, and the OBDII connector checked out. Tried resetting connection multiple times with no success either. Battery ground removed before each reset. Fuse's are fine as each scanner powers up per usual once connected.

Nothing has changed in the car between first and second iterations of the vendor tune besides removing battery cables each time.

First off, what could cause a loss of OBDII. Can that be inadvertently turned off by the tuner? I requested AC codes be permanently removed.

Second off, any suggestions on the transmission control issues?

Thanks in advance!

jcvett56

It's possible that the computers are bricked. That may explain the erratic driving behavior and also the communication error. Unfortunately, you may need to get a new ECM/TCM. I would send them back and see if that company can do a read on them for you. If they are having success reading them and no issue, then it's some wiring issue. I would reseat the connectors on the E38 and your T42 just to make sure it's seated properly. Also verify NO tabs on the computers are broken off which would result in a intermittent connection.

LSX Power Tuning

iTrader: (4)

Not sure its possible to make a computer not output to the odb2 port. I would agree that they could be bricked. If you want, you can send them to us and we can check them on a bench harness.

DrWagon

I've reseated the connecters multiple times now and the shop owner has given his ok that they are seated properly and the pins all look fine. What can cause the computer to brick? If they are bricked, will the car still start and idle fine?

The car had complete connectivity before being returned, so something would have happened in the shipping back to me if they successfully retuned before shipping right? I unboxed and plugged them in.

I will be heading in tonight to continue looking but I'm not happy if they are bricked and I have to buy new ones.

LSX Power Tuning

iTrader: (4)

They can get bricked by flashing the wrong year/OS into them using tuning software. Flashing the wrong year and OS into them can also make them still fire the vehicle up and the throttle not work correctly. Usually it will end up bricking the ecm throwing a P0606 code.

jcvett56

I'm not saying whoever you used bricked them on purpose and things do happen. But I would use some one respectable like LSX Power Tuning. Again not saying whoever you first used wasn't respectable just saying that you are now having an issue and maybe utilize LSX Power Tuning's expertise. Some people don't have the correct hardware/software to make the changes they want to happen. Have LSX Power Tuning set the ECM's up on his bench harness and see if he can find a solution for you!

DrWagon

I don't think it was bricked on purpose because that would be a pretty poor business model. Considering the various make/model components in my project, I'm more than willing to be patient getting the tune correct. I'm going through a reputable vendor/sponsor here that I chose because they developed one of my more specific aftermarket parts (I'm trying hard not to say the company name to not unnecessarily create bad press; they have been helpful up to this point). I also have a VVT engine, so that complicates the tuning part with an aftermarket cam.

In any event, if this vendor bricked the computers, they will be replacing them for me, at which point I'll get in touch with LSC Power Tuning to see what they can do for VVT tuning.