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OBD2 (a.k.a., OBDII, OBD II ) devices can be used to monitor the Volt's operation, clear codes, reduce insurance costs and....cause problems.
Reference Posts
http://gm-volt.com/forum/showthread.php?93121-Drivewise-driver-monitor
http://gm-volt.com/forum/showthread.php?10076-My-DashDAQ-blocked-OnStar-diagnostics
http://gm-volt.com/forum/showthread.php?58305-No-OnStar-Diagnostics-when-using-an-OBD2-device
http://gm-volt.com/forum/showthread.php?58305-No-OnStar-Diagnostics-when-using-an-OBD2-device
http://gm-volt.com/forum/showthread.php?15278-DEAD-VOLT-II
http://gm-volt.com/forum/showthread...tics-email-report-quot-could-not-connect-quot
http://gm-volt.com/forum/showthread.php?8770-DashDaq-data-acquisition-device
http://gm-volt.com/forum/showthread.php?5328-Volt-Diagnostic-Tool&p=90997#post90997
- Insurance Company Dongles
- Will plugging the device into my Volt cause problems?
- Workarounds for OBD2 Problems
- GM Policy on OBD2 Devices
- GM OBD2 Details
- Volt Has Two OBD2 (a.k.a. DLC) Ports
- GM approved OBD2 devices & those that aren't
- DashDAQ Information
- DashDAQ Volt License vs "GM enhanced" license.
- DashDAQ Volt parameters
- Insurance company OBD2 Dongles.
Some car insurers offer a discount for participating in a program called Drivewise. They send you a little dongle-like device which plugs into your OBD2 diagnostics port and records your driving habits. If you drive carefully, no panic stops, day vs night driving, mileage, etc. you get the discount. - Will plugging the device into my Volt cause problems?
It could cause a conflict between the dongle and On Star at a miniumum. It doesn't happen with every gadget plugged into the OBD port, but if your device causes an issue you may experience- Charging issues. Example: no longer charge on 120v or 240v…amber light comes on on the dash for 1 second then goes out and the charge fault indicator flashes red on the charge cord until removed from the port then resets itself back to green. Car then won't charge even with dongle removed.
- The monthly OnStar diagnostic reports may stop being sent.
- The monthly OnStar diagnostic reports may display this error message: "We were unable to successfully complete a diagnostic test. This issue may be caused by an aftermarket device plugged into your vehicle's diagnostic port."
- Workarounds for OBD2 Problems
- One option is to try removing the dongle every time you get out of the car.
- The OnStar Vehicle Diagnostic report will automatically transmit diagnostic data every 30 days on a predetermined date and time. You can remove the device on the date of download to ensure the email is sent.
- The older, "regular" OBD II tools may be less problematic than the newer CAN devices.
- Remove the device and continue to operate the car for a couple days (maybe use some mountain mode to build some charge) as once the network diagnostics continue to pass and everything operating correctly, the DTC depending on its "type" it may have already been set as HISTORY (the reason why OnStar would say no DTCs were present) but the fail-safe behavior that is inhibiting plug-in charging could eventually cease after a few trip cycles. However if it doesn't the dealer may have to clear certain "secured" DTCs using an appropriate scan tool.
- GM Policy on OBD2 Devices:
The Volt is not designed to have any non-GM device connected to either OBD port on the vehicle while driving. Any damage or problem caused by an aftermarket device in the OBD port will not be honored by your GM warranty. The networks accessible by the ports carry critical safety information at high speed between the control modules on the vehicle. So in the end, issues caused by an OBD2 device is a tool issue NOT a GM or Volt issue. - GM OBD2 Details
The data-link connector (DLC) aka diagnostic test port was/is designed for just that- periodic diagnostic testing, and not meant to be used as a permanent installation. The diagnostic routines built into these tools utilize code that is capable of temporarily interrupting or interfering with the normal data traffic flow within the car that is sometimes necessary when following a diagnostic routine for typically only for relatively short periods.
However Controller Area Network (CAN) peripherals such as the Scangauge, DashDAQ and others are doing is much more than that, as they are essentially being wired-in permanently as a “gauge” that attempts to become a foreign member of the car's network. Depending on how closely the tool manufacturer has followed the GMLAN protocol (GM’s own customized implementation of CAN) these tools should typically be completely benign under most conditions and settings, but certainly CAN become overly intrusive and disrupt various data transmissions, depending on the specific implementation being used. (i.e. which modules are being accessed, how many modules are being simultaneously accessed, which data packets are being requested, and how often) This is especially true in “gauge” modes where a collection of data from more than 1 module is being requested. Even GM’s own scan tool equipment (Multiple Diagnostic Interface with GDS2 software) does NOT passively display data from more than 1 module at a time, as these gauges attempt to do!
In the case of an OBD2 device causing issues, it likely does NOT have a specific agreement with GM (such as DashDAQ does) to access anything other than basic ECM/TCM diagnostics and the EPA regulated “fair-use” aspects of the OBD2 legislation and therefore their tool ( likely via back-door engineered PIDs) is creating data collisions and excessive wait-states that could trigger networking fault DTCs in various modules in the car which CAN result in certain immediate functionality loss for THAT ignition/trip cycle. However these usually will reset themselves on subsequent ignition/trip cycles. It’s very possible a particular ODB2 reset tool(barring an agreement with GM) might not be able to clear ALL DTCs from ALL modules used in the VOLT. Even so, tools/gauges such as this typically CANNOT permanently damage modules UNLESS their CAN/GMLAN receiver/transmitter (RX/XMTR) hardware is somehow placing excessive voltages on the network bus (it is typically limited to 3.5VDC) and thus damaging other RX/XMTR devices in other modules.
Use a DashDAQ if you really want to mess around looking at data, but you’ll also have to accept the possibility that it’s use might/will interrupt certain OnStar data collection features others might enjoy. But I’m pretty sure this is something Drew Technologies (the makers of the DashDAQ) are looking at as they have numerous contracts with GM to provide certain pieces of data acquisition equipment used in GM engineering. So it certainly seems they have an inside track there.
Regarding potential airbag interference, while the airbag control module (SDM) used in ALL GM cars and trucks is technically wired into the primary high-speed GMLAN network, it operates totally autonomously when it comes to airbag deployment due to a crash. It is specifically designed correctly and properly initiate frontal and side airbag deployment regardless of any network connection or traffic. However the specific exception to this would be for a vehicle roll-over that is designed to release the side curtain airbags when a roll-over event is detected. The roll-over sensor itself is not hard-wired to the SDM and is instead a member of the GMLAN network and thus "communicates" it’s detection of a roll-over event across the high-speed GMLAN bus to the SDM which deploys the curtains. Therefore THIS AND THIS ALONE (without a prior detected crash) would represent the only loss of airbag deployment functionality if a network failure (caused by an OBD2 device) was present at the time.
Conclusion: Do not use non-GM approved OBDII scanners in a Volt. - Volt: The Tale of Two OBD2 (a.k.a. DLC) Ports
According to the 2011 Volt service manual (page 12-248, Volume 3), the standard driver-side OBD-II connector provides access to a primary CAN bus that contains the emissions-related data required to be provided by all new cars. It also provides access to two additional data links - another GM-specific "chassis" CAN bus used for other various data without congesting the primary CAN bus and a GM-specific low speed CAN bus for sending less time-critical data.
The passenger-side connector provides access to a "high voltage energy management" CAN bus and also a separate "powertrain" CAN bus.
So, the driver and passenger side use the same physical connection standard but are wired differently and provide access to different data busses. The connector pins are assigned somewhat compatibly in that power is on pin 16 and scan tool ground is on pin 4. The energy management CAN is wired to pins 3 and 11 which are not used on the driver-side connector (but may be used on non-GM OBD-II connectors). The powertrain CAN bus uses pins 12 and 13 in a way that is electrically compatible with the chassis CAN bus on the same pins on driver-side connector.
The 2nd aux DLC (RH) really isnt a consideration here. The various networks are all technically "gatewayed" to the the primary DLC (LH) by specific modules that are present on more than one bus. So EVERYTHING should be available to the LH side DLC. In service the only real use of the RH DLC is for service programming of specific modules.
For those attempting to "backwards" engineer the GMLAN data streams, complete pin outs to both DLCs are at: http://gm-volt.com/forum/showthread.php?5328-Volt-Diagnostic-Tool&p=90997#post90997
- GM approved ODB2 devices:
DashDAQ
OBD2 Devices found to work:
OBD2 Devices to Avoid:
ScanGauge II
DriveSync - DashDAQ Information
DashDAQ is a small computer slightly bigger than a typical GPS, from Drew Technologies:
http://www.drewtech.com/enthusiast/index.html
It's powered off of the OBDII bus, and very flexible. Drew has a license deal with GM and gets lots of technical data from them - so the DashDAQ can pull a lot of kinds of data out of the CANBus traffic.
How it can be used:
http://gm-volt.com/2012/06/27/dashda...d-the-curtain/
Some things are missing - HVAC power and charger plug power. But I am watching battery power flow and usable charge, and power flow for both traction motors, and have an equation for power from the engine. - DashDAQ Volt License vs "GM enhanced" license.
The Volt license has to purchased over the phone by calling Drew Technologies.
The GM license is for all other GM cars but does not have the parameters specific to the Volt. The Volt license will not work on other GM cars. However, the installed generic parameters database should give anywhere from 30-60 parameters (with 60 for 2010 and newer cars) and should give most non-Volt car owners everything they need unless they want to do advanced troubleshooting on their own.
Note, the Volt "Extension" isn't an extension at all. You can either have all the generic OBD scanning codes, plus the GM extensions or you can have the Volt "extensions". Loading up the Volt driver excludes any other J1962 drivers (which includes ALL the other OBD drivers they seem to have).
So if you're interested in Volt-special type stuff, you can't see any of the things you'd normally expect to see with any other car. If you operate 100% EV, that's not too much of a problem. But if the ICE turns on, about the only things you can see are RPMs, Torque, and coolant temps. Specifically, there's no way to estimate instantaneous MPGs, as the MAF isn't available and there's absolutely no way to estimate it. - DashDAQ Volt parameters:
DashDAQ Available Signals Report
Time: Wed Oct 13 14:27:10 2010
Firmware Version: DashGUI-2.1.4-2024
Device: a-GM Specific (volt) Version:2.1.4-2024 (Base)
9998 "Latency" "OBD Latency" "ms" 0
9999 "Updates" "OBD Update Rate" "Hz" 0
1586 "APP" "Accelerator Pedal Position" "%" 0
1573 "APM Crnt" "Accessory Power Module Current" "A" 0
1569 "APM Temp1" "Accessory Power Module Temperature 1" "°C" 0
1570 "APM Temp2" "Accessory Power Module Temperature 2" "°C" 0
1574 "APM Volt" "Accessory Power Module Voltage" "V" 0
1549 "ACCM Pow" "Air Conditioning Compressor Power" "kW" 0
1507 "ACCM PowLim" "Air Conditioning Compressor Power Limit" "kW" 0
1548 "ACCM Spd" "Air Conditioning Compressor Speed" "RPM" 0
1604 "AC HSP" "Air Conditioning High Side Refrigerant Pressure" "kPa" 0
1547 "AC LSP" "Air Conditioning Low Side Refrigerant Pressure" "kPa" 0
1552 "AC LST" "Air Conditioning Low Side Refrigerant Temp" "°C" 0
1564 "Amb Air Tmp" "Ambient Air Temp" "°C" 0
1594 "AuxPmp Spd" "Auxiliary Transmission Pump Speed" "RPM" 0
1581 "Axle Tq" "Axle Torque (Actual)" "Nm" 0
1584 "Axle Tq Immd" "Axle Torque Commanded (Immediate)" "Nm" 0
1580 "Axle Tq Pred" "Axle Torque Commanded (Predicted)" "Nm" 0
1509 "CHCM Cmd" "Cabin Heater Power Cmd" "kW" 0
1508 "CHCM Req" "Cabin Heater Power Req" "kW" 0
1544 "Proximity" "Charge Coupler Proximity Voltage" "V" 0
1603 "TPS" "Commanded Throttle Position" "%" 0
1563 "HCP Mdl Vlt" "Control Module Voltage (HCP)" "V" 0
1562 "DistTravl CC" "Distance Traveled Since Code Clear" "Km" 0
1560 "MIL on Dist" "Distance Traveled with MIL On" "Km" 0
1585 "Total Axl Tq" "Driver Intended Axle Torque" "Nm" 0
1583 "Total Brk Tq" "Driver Intended Brake Torque" "Nm" 0
1554 "ESS AC Cmd" "Energy Storage System AC Comp. Power Cmd" "kW" 0
1553 "ESS AC Req" "Energy Storage System AC Comp. Power Req" "kW" 0
1512 "ChrgngPowLim" "Energy Storage System Charging Power Limit" "W" 0
1610 "ESS CondReq" "Energy Storage System Conditioning Mode Req" "" 0
1611 "ESS CondStat" "Energy Storage System Conditioning Mode Stat" "" 0
1527 "ESS Pmp Cmd" "Energy Storage System Coolant Pump Cmd" "%" 0
1515 "ESS Pmp" "Energy Storage System Coolant Pump Spd (%)" "%" 0
1528 "ESS Pmp Spd" "Energy Storage System Coolant Pump Spd (RPM)" "RPM" 0
1607 "ESS Vlv Cmd" "Energy Storage System Coolant Valve Cmd" "" 0
1608 "ESS Vlv Pos" "Energy Storage System Coolant Valve Pos" "" 0
1511 "ESS Htr Cmd" "Energy Storage System Heater Cmd" "kW" 0
1541 "ESS Htr Cmd" "Energy Storage System Heater Cmd (%)" "%" 0
1510 "ESS Htr Req" "Energy Storage System Heater Req" "kW" 0
1505 "ESS Inlet" "Energy Storage System Inlet Temp" "°C" 0
1506 "ESS Outlet" "Energy Storage System Outlet Temp" "°C" 0
1568 "Eng Act Trq" "Engine Actual Torque" "Nm" 0
1598 "ECT" "Engine Coolant Temperature" "°C" 0
1599 "Eng RPM" "Engine Speed" "RPM" 0
1500 "CRFM" "Front End Cooling Fan Spd Cmd(%)" "%" 0
1543 "Htr Vlv Cmd" "Heater Core Coolant Valve Cmd" "%" 0
1609 "Htr Vlv Pos" "Heater Core Coolant Valve Position" "" 0
1551 "Htr Vlv Pos" "Heater Core Coolant Valve Position (%)" "%" 0
1523 "HV Temp" "High Voltage Battery Average Temp" "°C" 0
1524 "HV Crnt" "High Voltage Battery Current" "A" 0
1504 "HV Cap" "High Voltage Battery Estimated Capacity" "A-Hr" 0
1520 "LT ChrgPow" "High Voltage Battery Long Term Charge Power" "kW" 0
1519 "LT DschrgPow" "High Voltage Battery Long Term Discharge Power" "kW" 0
1517 "HV Max Vlts" "High Voltage Battery Max Cell Voltage" "V" 0
1521 "HV Max Temp" "High Voltage Battery Max Temp" "°C" 0
1516 "HV Min Vlts" "High Voltage Battery Min Cell Voltage" "V" 0
1522 "HV Min Temp" "High Voltage Battery Min Temp" "°C" 0
1542 "HV SOC" "High Voltage Battery State of Charge (VICM)" "%" 0
1550 "HV SOC Gauge" "High Voltage Battery State of Charge Gauge Position" "%" 0
1518 "HV Volts" "High Voltage Battery Voltage" "V" 0
1606 "HV Faults" "High Voltage System Fault Status" "" 0
1612 "Hood Sw" "Hood Switch Position" "" 0
1503 "Aux Fan Cmd" "Hybrid Auxiliary Fan Cmd" "%" 0
1513 "Aux Fan Spd" "Hybrid Auxiliary Fan Spd (%)" "%" 0
1502 "Aux Fan Spd" "Hybrid Auxiliary Fan Spd (RPM)" "RPM" 0
1576 "HV Crnt" "Hybrid Battery Discharge Current (HCP)" "A" 0
1577 "HV Max Temp" "Hybrid Battery Max Temp (HCP)" "°C" 0
1578 "HV Min Temp" "Hybrid Battery Min Temp (HCP)" "°C" 0
1575 "HV SOC" "Hybrid Battery State of Charge (HCP)" "%" 0
1602 "IAT" "Intake Air Temperature" "°C" 0
1605 "MAP" "Intake Manifold Vacuum Pressure" "kPa" 0
1615 "MtrA State" "Motor A Inverter State" "" 0
1592 "MtrA Spd" "Motor A Speed" "RPM" 0
1595 "MtrA Temp" "Motor A Temp" "°C" 0
1589 "MtrA Tq" "Motor A Torque" "Nm" 0
1588 "MtrA Tq Cmd" "Motor A Torque Cmd" "Nm" 0
1616 "MtrB State" "Motor B Inverter State" "" 0
1593 "MtrB Spd" "Motor B Speed" "RPM" 0
1596 "MtrB Temp" "Motor B Temp" "°C" 0
1591 "MtrB Tq" "Motor B Torque" "Nm" 0
1590 "MtrB Tq Cmd" "Motor B Torque Cmd" "Nm" 0
1561 "NumWrmUpsCC" "Number of Warm Ups Since Code Clear" "Cnt" 0
1530 "OBCM AC Crnt" "On Board Charger AC Input Current" "A" 0
1529 "OBCM AC Vlts" "On Board Charger AC Input Voltage" "V" 0
1532 "OBCM HV Crnt" "On Board Charger High Voltage Output Current" "A" 0
1536 "OBCM HV Pow" "On Board Charger High Voltage Output Power" "kW" 0
1531 "OBCM HV Vlts" "On Board Charger High Voltage Output Voltage" "V" 0
1534 "OBCM LV Crnt" "On Board Charger Low Voltage Output Current" "A" 0
1537 "OBCM LV Pow" "On Board Charger Low Voltage Output Power" "kW" 0
1533 "OBCM LV Vlts" "On Board Charger Low Voltage Output Voltage" "V" 0
1535 "OBCM Temp" "On Board Charger Temperature" "°C" 0
1545 "OAT" "Outside Air Temperature" "°C" 0
1546 "Filterd OAT" "Outside Air Temperature Filtered" "°C" 0
1501 "PECL Temp" "Power Electronics Coolant Loop Temp" "°C" 0
1525 "PE Pmp Cmd" "Power Electronics Coolant Pump Cmd" "%" 0
1514 "PE Pmp" "Power Electronics Coolant Pump Spd (%)" "%" 0
1526 "PE Pmp Spd" "Power Electronics Coolant Pump Spd (RPM)" "RPM" 0
1582 "Regen Tq" "Regen Braking Axle Torque (Estimated)" "Nm" 0
1579 "Regen Tq Req" "Regen Braking Axle Torque Req" "Nm" 0
1601 "Sprk Adv" "Spark Advance" "°" 0
1614 "Sys Pwr Md" "System Power Mode" "" 0
1538 "AC Energy" "Total AC Energy Used Durning Last Charge" "kW-hr" 0
1540 "HV Energy" "Total HV Energy Used Durning Last Charge" "kW-Hr" 0
1539 "LV Energy" "Total LV Energy Used Durning Last Charge" "kW-Hr" 0
1566 "Trans OutSpd" "Tranmission Output Speed" "RPM" 0
1555 "C1 Slip" "Transmission C1 Clutch Slip" "RPM" 0
1556 "C2 Slip" "Transmission C2 Clutch Slip" "RPM" 0
1557 "C3 Slip" "Transmission C3 Clutch Slip" "RPM" 0
1558 "C4 Slip" "Transmission C4 Clutch Slip" "RPM" 0
1559 "C5 Slip" "Transmission C5 Clutch Slip" "RPM" 0
1613 "Trans Md" "Transmission Mode (Hybrid)" "" 0
1565 "Trans Temp" "Transmission Oil Temp" "°C" 0
1567 "Trans Ratio" "Transmission Ratio" "" 0
1600 "Veh Spd" "Vehicle Speed" "Km/Hr" 0
Notes:
The DashDAQ isn't actually getting measurements on power. It's querying for amps and volts.
1613 Trans Mode is just the selected shifter (P,R,N,D,L) position
Need even more? See http://gm-volt.com/forum/showthread.php?8770-DashDaq-data-acquisition-device
Reference Posts
http://gm-volt.com/forum/showthread.php?93121-Drivewise-driver-monitor
http://gm-volt.com/forum/showthread.php?10076-My-DashDAQ-blocked-OnStar-diagnostics
http://gm-volt.com/forum/showthread.php?58305-No-OnStar-Diagnostics-when-using-an-OBD2-device
http://gm-volt.com/forum/showthread.php?58305-No-OnStar-Diagnostics-when-using-an-OBD2-device
http://gm-volt.com/forum/showthread.php?15278-DEAD-VOLT-II
http://gm-volt.com/forum/showthread...tics-email-report-quot-could-not-connect-quot
http://gm-volt.com/forum/showthread.php?8770-DashDaq-data-acquisition-device
http://gm-volt.com/forum/showthread.php?5328-Volt-Diagnostic-Tool&p=90997#post90997