OBD Port Trans Issues?

[craigtone]

I have an '03 A6 4.2L. It currently has 150k on the clock and the trans was rebuilt at 93K. I won't say I am a conservative driver and actually usually have my right foot into it!

I recently installed a Waylens Horizon windshield mount camera that has a bluetooth OBD module to add real-time stats to the recorded video. The first long trip (>2 miles) with the OBD module installed, I had a series of 2 "slams" out of the transmission while cruising about 45MPH on a straight stretch of road. I immediately thought "Oh Sh*t!" ... 4.2L trans troubles but then it acted fine. A few days later I drove it to the store and had another slam and a bad slip pulling into the parking lot. I came out of the store and pulled the OBD module and since then, I have not had any trans malfunctions.

Has anyone ever heard of something plugged into the OBD port causing trans issues?

[G0to60]

Yep, I had this same problem a few years ago when I had a bluetooth OBD module for my Torque app. I had the same symptoms as you and narrowed it down to the OBD module so now I only use it when I'm stationary to check codes and such. I've also talked with a few people who have noticed this same thing when driving with something plugged into the OBD port.

When I asked this same question someone mentioned that it might be due to the module requesting too much information at one time and it essentially bogged down the ecu so when it was time to shift things got screwy. I'm not sure if this is true but it makes sense to me. I'll see if I can find my old thread about it.

[carmudgeon]

Interesting, I've had the occasional same issue, never thought of the OBD2 adapter causing an issue with the CANBUS.

[LakeTahoeQuattr]

Yes indeed this also happened to me when I had my tiptronic in my allroad only. It did not happen in my tiptronic 4.2 or tiptronic 2.8. Same symptom, Crusing on the freeway at 70mph and SLAM!!! Did it a few times on a few different days before I was able to pin point the relationship between the two. It only did it with elm327 obd 2 BT module plugged in and torque running. I believe it did it also with torque not running but BT device plugged in. There is some sort of canbus glitch. Now with manual trans installed no issues obviously.