OBD2 Data Logger: Easily Log & Convert OBD2 Data

Do you want to analyse data from your car?

Maybe you're doing vehicle prototype tests - or simply optimizing your own driving. To do so, you’ll need data on e.g. vehicle speed, RPM, MAF, throttle position etc.

You can get this via OBD2 - and several OBD2 scanners of course exist.

However, very few let you easily log your OBD2 data to an SD card for post-analysis.

This is where the CLX000 is the perfect OBD2 logger solution:

Simply connect the logger to your car to record data to the SD. Extract the data via USB when you're done. And easily convert the data with our free CANvas software!

In this guide, we briefly outline the following:

  • The pros & cons of working with the OBD2 standard
  • How you can easily configure the CLX000 to log OBD2 data via CANvas
  • How you can use CANvas to convert raw OBD2 data to human-readable form
  • Results: An example of OBD2 output data from an Audi A4 (speed & RPM)
OBD2 Data Logger OBD Recorder

For a quick intro, check out our 5 min video above, showing how the OBD2 data logging works in practice!




The Pros & Cons of OBD2

Before we head in, let’s do a quick recap on the basics of OBD2:

What makes OBD2 interesting is that the rules for converting the raw OBD2 data into human-readable form are publicly available - cf. e.g. Wikipedia’s guide on OBD2 PIDs.

This contrasts the raw CAN bus data of most cars which requires that you access proprietary OEM conversion rules - or “hack your car” and reverse engineer the data.

However, despite this added simplicity there are two challenges with OBD2 data:

  • First, your OBD logger needs to be set up to “request” the messages you want
  • Second, you’ll need to e.g. set up a script to convert the raw OBD2 data

To make this practical, you'll want a solution with built-in OBD2 support.





LOG OBD2 DATA IN 3 SIMPLE STEPS

The CLX000 and our free CANvas software make OBD2 logging easy:

  • In CANvas, configure your OBD2 data logger to request OBD2 PIDs from a list of Mode 01 PIDs (or add your own)
  • Connect the CLX000 to your car with a DB9-OBD2 adaptor cable
  • Use CANvas to quickly convert your raw OBD2 data via the built-in OBD2 PIDs database
OBD2 Data Logger E2E Request Query OBD-II PIDs Convert


1

Configure your CAN logger to request OBD2 messages

First, you'll configure your CLX000 to log OBD2 data:

  1. Connect your logger to your PC via USB
  2. Open CANvas and go to the “CONFIGURE CANLOGGER”
  3. Click the “Transmit list” tab
  4. Click the “load” icon to choose from a list of OBD2 PIDs
  5. Save the config on your logger’s SD card and eject
Configure OBD2 Data Logger Transmit Request OBD II PIDs

Not all cars support all the standard Mode 01 OBD2 parameters. While newer cars often support a wide range, this can lead to confusion as you may request e.g. Vehicle Speed - and get no data back.

You'll be able to spot this as you'll have a lot of "7df" request ID messages - but no corresponding "7e8" responses.

Luckily, you can check what Mode 01 parameter IDs are supported for OBD2 in your car.

OBD2 Data Log PIDs

You do this by configuring your CLX000 to request the "Supported PIDs" parameters the first time you log data from your vehicle. These PIDs have ID 00, 20, 40, 60, 80, A0 and C0 - which you can select in CANvas.

You can download a pre-made configuration file (config.xml) that you can load in CANvas HERE. Note that it's set up for a CL2000, though this can quickly be adjusted to match your logger using CANvas.

This will send a "single-shot" request for these PIDs with a small delay between each. Once you've recorded this data, you can take the log file and convert it via CANvas' built-in OBD2 conversion rules. The resulting output will be a list of all the Mode 01 PIDs with a boolean value, telling you if the PID is supported or not.

Based on this, you can then update your transmit list in CANvas to only request valid PIDs.

Note on CAN bus vs. other OBD2 protocols: OBD2 can be based on five different protocols. The most commonly used is CAN bus, as it's been made mandatory in USA for cars produced after 2008. As a result, CAN is also used in most vehicles produced outside USA since 2008, but not consistently so. If your car is produced outside USA or before 2008, it is not necessarily possible to record OBD2 data via the CLX000 (as it supports only CAN bus). Often you can check the protocol via the OBD2 connector pins





2

Connect Your CLX000 to Your Car's OBD2 Port

Now your CLX000 is ready to log OBD2 data! Easy, right?

Next, simply connect it to your car's OBD2 connector port.

You'll find this below the steering wheel and you'll need a DB9-to-OBD2 adaptor.

The OBD2 logger will now log OBD2 data to the SD when you turn on the car.





1

Convert your raw OBD2 data

Ok, so you’re now back at your PC with your CLX000 - now filled with OBD2 raw data from your car.

It's time to convert the raw OBD2 data into readable form:

  1. First, load the log files to your PC via USB
  2. Open CANvas and go to CONVERT DATA
  3. Click the database icon to load the OBD2 database
  4. Go to ‘Load Log Files’ and find your data files
  5. In ‘Manage Log Files’, select 'scaled engineering values'
  6. Click the green play button - and that's it!

You can of course adjust your output with e.g. Log File Merging and Downsampling

OBD2 Data Convert Human-Readable OBDII PIDs Wikipedia Database CANvas



The Result: OBD2 Data Made Easy

In short: With the CLX000, it's a breeze to log OBD2 data from your car.

Below you can see an example of speed (km/h) and RPM logged in an Audi A4 with a CL2000 on the highway.

You can of course check out the converted data - or play around with the raw OBD2 data sample yourself in CANvas.

OBD2 Data Logger Audi A4 Sample Speed RPM

Start logging your own OBD2 data with the CLX000 now!





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