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Payco
28
May 24, 2017
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From what I understand, Chevy has some proprietary modifications to CANBUS on their models. Do y'all know how well this device will work with a 2016-17 Volt?
Carloop
68
Carloop
May 24, 2017
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Paycotl;dr You will be able to get a ton of information with Carloop on the Chevy Volt - confirmed.
When you connect Carloop to the Primary OBD-II port on the Chevy Volt, you will be able to read and write CAN bus messages to GMLAN High Speed 1 bus. "GMLAN" stands for GM Local Area Network and it is the name used by GM for what every other OEM in the industry calls Controller Area Network (CAN). The made no modifications to the CAN bus protocol whatsoever, they just call it GMLAN High Speed or Medium Speed.
In the case of the Chevy Volt, there are 3 different CAN buses that appear on the Primary OBD-II connector. GMLAN 1 High Speed (pins 6 and 14), GMLAN 2 High Speed (pins 13 and 12) and GMLAN Medium speed (pins 3 and 11). Since Carloop maps pins 6 and 14 to the Particle's Photon CAN bus you only have access to GMLAN 1.
There is actually a 4th CAN bus that doesn't terminate on the Primary OBD-II port but is internal to the vehicle. It connects the instrument cluster, the GPS module, etc. This is just a single wire (as opposed to twisted pair for CAN) and it is called GMLAN Low Speed. It runs at a meager 33.3 kbps but is enough to transmit data for a few modules over a single wire.
You may have noticed I mentioned "Primary" OBD-II port above. That is because there is an "Auxiliary" OBD-II port on the Chevy Volt. Yes, a second OBD-II in the passenger footwell. This Auxiliary OBD-II port has additional CAN buses that strictly deal with the battery and hybrid system. Unfortunately, Carloop will not be able to read CAN messages from the Auxiliary OBD-II port, because pins 6 and 14 are not populated.
When you connect Carloop to the Primary OBD-II port on the Chevy Volt, you will be able to read and write CAN bus messages to GMLAN High Speed 1 bus. "GMLAN" stands for GM Local Area Network and it is the name used by GM for what every other OEM in the industry calls Controller Area Network (CAN). The made no modifications to the CAN bus protocol whatsoever, they just call it GMLAN High Speed or Medium Speed.
In the case of the Chevy Volt, there are 3 different CAN buses that appear on the Primary OBD-II connector. GMLAN 1 High Speed (pins 6 and 14), GMLAN 2 High Speed (pins 13 and 12) and GMLAN Medium speed (pins 3 and 11). Since Carloop maps pins 6 and 14 to the Particle's Photon CAN bus you only have access to GMLAN 1.
There is actually a 4th CAN bus that doesn't terminate on the Primary OBD-II port but is internal to the vehicle. It connects the instrument cluster, the GPS module, etc. This is just a single wire (as opposed to twisted pair for CAN) and it is called GMLAN Low Speed. It runs at a meager 33.3 kbps but is enough to transmit data for a few modules over a single wire.
You may have noticed I mentioned "Primary" OBD-II port above. That is because there is an "Auxiliary" OBD-II port on the Chevy Volt. Yes, a second OBD-II in the passenger footwell. This Auxiliary OBD-II port has additional CAN buses that strictly deal with the battery and hybrid system. Unfortunately, Carloop will not be able to read CAN messages from the Auxiliary OBD-II port, because pins 6 and 14 are not populated.
Payco
28
May 24, 2017
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CarloopThanks! I know there's probably a bit of a conflict of interest here but: the other iffy thing I've heard is that some OBDII DAQs were causing problems on the gen1 Volt. Am I correct in assuming reading from CAN couldn't cause those problems, or does a dongle have to send some active signals to gain read access to the bus or something? If the former, does the device have a permissions system to lock out message-writing in the general case? I'm much more interested in gathering data on a daily basis, and can only imagine writing messages to the bus under controlled situations. Speaking of, what are the most common use cases your customers have for dispatching messages the system?
Carloop
68
Carloop
May 24, 2017
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PaycoReading CAN messages causes no problem whatsoever and they are broadcast on that bus so you will have no problem reading them.
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