Problems with leaving OBD2 Bluetooth Reader plugged in

[chumbie]

My 2008 535XI would not turn over this past weekend. Also ABS and DSC Malfunction was displayed. I suspected low battery voltage so checked the under-hood terminals and the battery directly. They were ~9.5V and 10.5V resp. Put the charger on for 2 hours and the car started. Shut it down and charged for another 2 hours. Next morning, wouldn't turn over. Charged it for 4 hours and drove to BMW dealership. 20 minutes after I arrived, they tried to take it to a bay but it was dead. They asked me to authorize a full load test at ~$300. Service tech noticed the ODB2 reader was plugged in and asked for how long had it been plugged in. I told him a day or two. He said that his diagnostic tester showed 'some modules' being turned on and off 52 times overnight. He also said that the ODB2 reader jumps two pins on the socket which keeps the CAN bus active. I can believe it but not sure why something would cause any modules to be turn on or off. Service Tech also said that the battery was likely no good. I told him that the battery is only 3 weeks old. He said that after only a few deep cycle draws, batteries can't pass a load test. So we took it out, I took the shuttle to the nearest retailer in case there was a warranty claim.... it failed the load test. Got a new battery and headed back to the dealership. They installed it and started the overnight tests. That was yesterday.

This afternoon's info from the service rep is that one of the modules is drawing power and they're still checking. Just thought I'd let you guys know about this issue. On my E39, I used to keep the same ODB2 reader plugged in all of the time.... without any problems. I still have extended warranty coverage but not sure if it'll help in this case. Things usually have to break or fail before they'll step in. I'll follow up this post as things develop.

[Nick91303]

My 2008 535XI would not turn over this past weekend. Also ABS and DSC Malfunction was displayed. I suspected low battery voltage so checked the under-hood terminals and the battery directly. They were ~9.5V and 10.5V resp. Put the charger on for 2 hours and the car started. Shut it down and charged for another 2 hours. Next morning, wouldn't turn over. Charged it for 4 hours and drove to BMW dealership. 20 minutes after I arrived, they tried to take it to a bay but it was dead. They asked me to authorize a full load test at ~$300. Service tech noticed the ODB2 reader was plugged in and asked for how long had it been plugged in. I told him a day or two. He said that his diagnostic tester showed 'some modules' being turned on and off 52 times overnight. He also said that the ODB2 reader jumps two pins on the socket which keeps the CAN bus active. I can believe it but not sure why something would cause any modules to be turn on or off. Service Tech also said that the battery was likely no good. I told him that the battery is only 3 weeks old. He said that after only a few deep cycle draws, batteries can't pass a load test. So we took it out, I took the shuttle to the nearest retailer in case there was a warranty claim.... it failed the load test. Got a new battery and headed back to the dealership. They installed it and started the overnight tests. That was yesterday.

This afternoon's info from the service rep is that one of the modules is drawing power and they're still checking. Just thought I'd let you guys know about this issue. On my E39, I used to keep the same ODB2 reader plugged in all of the time.... without any problems. I still have extended warranty coverage but not sure if it'll help in this case. Things usually have to break or fail before they'll step in. I'll follow up this post as things develop.

If you don't mind me asking what type of OBD reader are you referring to??

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[chumbie]

It is a generic ELM 327 purchased off Ebay. I'll have to wait until I get my car back to check the manuf. & model.

[Nick91303]

It is a generic ELM 327 purchased off Ebay. I'll have to wait until I get my car back to check the manuf. & model.

Oh ok. Because I ordered one of them " obdII tuners" and same thing. Left it in the port and car dash said low voltage.. but I also have carly and leave that plugged in all the time and have never had a issue with that one. But that has a on off button.

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[chumbie]

Apparently the key thing is if the ODB reader has a jumper which bridges those two pins on the socket. If it has that jumper, it doesn't matter if the reader is on or off.