OBDII Auto diagnostics

How to peer into the soul of your engine

As I’ve grown older one of my regrets in my car owning life has been how, over the years, I’ve been able to less and less work on the engine. In the good old pre electronic days one could tinker to your hearts content under the bonnet. These days modern cars are designed with fewer and fewer user serviceable components. Electronic diagnostic systems
have been introduced and engine tuning now has to done by the dealers using expensive       computer guided system. The only task left to the car owner now is routine service and maintenance, but what about us who want to see deeper into the engine and see just what is going on?

In the early eighties manufacturers standardised on a diagnostic system for all cars, this was designed to allow garages and service centres to use newly available analysis equipment to give hitherto masses of information about the performance of every component of a cars engine. Part of this new standard was the consolidation of a set of error codes or DTCs and the design of a standard diagnostic socket or interface which has been fitted to most cars since the early nineties. The latest incarnation of this standard is called OBD II (On Board Diagnostics) and an OBDII socket will usually be found near the fuse box or accessible from inside the car - check your car manufacturers data sheet and handbooks for further information.

Several years ago an ODBII interface came with a specially designed plug and data lead which usually interfaced to a PC or laptop. Using either manufactured specific or general purpose software the error code and other diagnostic information from the engine could be accessed. As most modern cars employ a computerised Engine Management System data could also be sent back to the engine to set or change electronic settings stored on the on board computer. Today most ODBII dongles are cordless using Bluetooth to communicate to a personal computer running diagnostic software. The growth in the use of Android based devices such as tablets and smartphones has created a great pairing of the use of a Bluetooth enabled OBDii dongle with a an Android device running diagnostic software.  Data can be logged and viewed from the engine while the car is running over long distances not just at the garage.

A Bluetooth enabled ELM327 dongle can be purchased cheaply from many online suppliers though documentation can be sparse and you may have to search online and do further research to obtain lists of error codes and how to connect to the device using Bluetooth.

You will also need a Bluetooth enabled Android device and get it to connect to the dongle, for security purposes this connection has to be made using username and password validation. A good start in exploring the world of diagnostic software is Torque which you will be able to download from the Android Appstore. There s a free version and an premium version, on of my favourite features of Torque is the “Head Up Display” mode where the data display screen is inverted as if seen in a mirror. Placing your Android device under the windscreen allows you to watch and monitor your engines changing state whilst driving. I should also mention that’s it’s illegal to do this in most juristrictions though

A word of warning - there is the potential to seriously mess with the tuning of your cars engine using a combination like this so don’t say I didn’t warn you. Happy investigating!

ELM327 Bluetooth OBDII Dongle

ELM327 Bluetooth OBDII dongle
Credit: Amazon