What is OBD2? OBD2 stands for On Board Diagnostics version 2. The US government mandated that all vehicles sold in the US beginning with 1996 model year comply with a minimum set of diagnostic functions. These functions were primarily intended for vehicle service, inspection and emissions testing. However, the specification allows for real-time monitoring of many vehicle sensors. This real-time monitoring comes in handy when tuning a high performance vehicle and also when racing to inform the driver of engine conditions.

But there are some limitations to the OBD2 functionality. First, manufacturers are not required to output all sensor data. Only a minimum set of data. Second, depending on the protocol used, the specification requires a certain amount of time after a message is recieved before data can be requested again. The reason this is an issue is becuase the ECU does not stream data. Instead, each sensor data has to be requested. When the ECU recieves a request, it then outputs data for the sensor requested. When the R1000 displays a single sensor, the update rate is 8 times per second. When displaying 2 sensors, the update rate is 4 times per second. For 3 sensors the update rate is 3 times per second (ISO9141 and ISO14230). For this reason, it may not be advantagous to display more than 3 sensors at a time. There are some OBD2 dataloggers on the market that claim as little as 1ms accuracy. This might sound good, but it's misleading because the absolute fastest update time that can be achieved using the ISO9141 protocol is 120ms. Which is when requesting only 1 sensor data.

Up until MY2008, the OBD2 specification did not require a manufacturer to use a specific communication protocol, so long as it was one of the ones listed below. Most import vehicles used the ISO9141 protocol, which the R1000 is compatible with. Ford, GM and late model Chrysler vehicles used the J1850 protocol. Compatibility with this protocol is not currently planned. Starting with MY2008, new vehicle models must use the CAN bus protocol. Compatibility with this protocol is supported by the R1000 for most vehicles that use it, however we have found that some vehicles are not entirely OBD2 compliant and data requests are frequently ignored.

The OBD2 diagnostic port connector is usually in the drivers footwell and is powered. So, there is only 1 cable to hook up. Installation is nothing more than plugging in the data link cable to the OBD2 connector.

Please note that when the vehicle ECU has stored DTC's, it may not output current sensor values. If you suspect that data being displayed is incorrect, then make sure all DTC's have been cleared. It is impossible for our OBD2 gauges to show incorrect data as there is error checking as part of the communication protocol. The data values displayed on the screen are the values that the vehicle ECU is sending to the OBD2 gauge.

There are a total of 5 protocols in use with 2 "flavors" of CAN:

Beginning with model year 2008, all vehicles sold in the United States must use the ISO15765 protocol for diagnostics. Some manufacturers started to make the switch to this protocol as early as MY2002. Here is a handy chart showing protocol usage since 1996 for most vehicle makes and models.

A partial list of DTC's can be found on the codes page.