Diagnostics Technical Information

Diagnostics

What is the difference between ALDL and OBD2 cables?

In short, the two diagnostic cables speak different ‘languages’ which are required to communicate to different vehicles.

For a more indepth explanation, please see our dedicated page found here.

What diagnostic protocol does my commodore use?

Below I have made a little table which indicates which protocols are used in which commodores. (Note: VPW, HSCAN and GMLAN are all OBD2 protocols)

ALDL VPW HS CAN GMLAN
VR V6/V8 YES NO NO NO
VS V6/V8 YES NO NO NO
VT V6/5.0L V8 YES NO NO NO
VT LS1 V8 YES YES NO NO
VX V6 YES NO NO NO
VX LS1 V8 YES YES NO NO
VY V6 YES NO NO NO
VY LS1 V8 YES YES NO NO
VZ V6/LS2 V8 YES NO YES NO
VZ LS1 V8 YES YES NO NO
VE V6/V8 NO NO YES YES
VF V6/V8 NO NO YES YES

How do I upgrade to a newer diagnostic protocol?

In short, its a big job. (Only worth it for an engine conversion!)

As for the long answer, this is best answered using an example, such as a VY V6.

In a VY V6, the engine computer (ECU/ECM) communicates over ALDL. The hardware in the ECU is physically not capable of communicating over any OBD2 protocol as they require additional hardware and firmware, so basically its not possible.

In saying that, a VY V6 could have an aftermarket ECU fitted, or factory LS1 V8 ECU, or even something newer like an E38 ECU. This does require custom wiring, tuning and alot of ‘know how’ to get an ECU working which was never intended for use with that specific engine.

Its more commonly found that the corresponding engine for the ECU is also swapped into the car (ie. LS1 V8 conversion), which makes engine compatibility not a problem. Realistically this would be the easiest option, plus has the added bonus of likely upgrading to a better engine!

What is a good cheap diagnostic scantool?

The old saying “you get what you pay for” couldn’t be more accurate when it comes to diagnostic scantools.

Scantools are extremely complex pieces of hardware, which have to perform complex tasks to decode protocols on a microsecond level (thats 1/100,000 of a second!). The average OEM tool and software are in excess of multi-thousands of dollars which also tend to have muti-thousand dollar yearly subscriptions. This is obviously not affordable for the average joe, which is why software developers such as ourselves develop cheaper solutions!

One of the common questions we receive is “why doesn’t my $10 ELM cable read my fault codes?”

Now just thinking about that value, $10aud.
What does that really get you in this day of age.. maybe two coffee’s or a pint of beer?
No matter how you look at it, its not much!

Now, what do you really think a $10 scantool will give you?
The first thought that should spring to mind is ‘Not much’, which is exactly right. Cheap tools tend to be missing parts, or missing compatible software, since hardware is basically useless without good software to go with it!

The difference with our tools is that we develop software specifically designed for our indicated supported vehicles which is why our applications are capable of reading vehicle specific information, and performing more complex tasks such as identifying vehicle specific fault codes using OEM diagnostic routines.

Scantools are basically an investment. When you consider the average car cost is between $5k-35k, the investment into a diagnostic tool is an extremely good idea as it results in saving thousands on diagnostic bills and trips to dealerships. We hope that our tools make for a good investment, to help the average joe diagnose their vehicle using top quality tools but at a fraction of the cost of genuine tools.

Technical

What is J2534?

J2534 is an SAE protocol designed to standardize the connection between scantools (Hardware) and software.

So, whats that mean in English?
Essentially, J2534 is a set of rules/commands which both the scantool and the software must follow. This allows development of hardware and software to be much faster as there is a defined communication method already in place.

It allows hardware manufactures to develop a tool without having to specifically tailor design it for a software company. And also allows software developers to make complex application which will work with any J2534 compliant scantool.

As seen above the J2534 protocol is the communication between the hardware and software, it is not a direct communication to the vehicle (Such as CAN, ALDL or VPW). Instead, the J2534 is a predefined method of controlling hardware which will speak to the vehicles communication line.

J2534 has also been designed to be expandable. Basically it has been designed so that it future proof, to allow new features to be added through firmware updates in the hardware. For example, the new v5 API allows detecting scantools available prior to connection (Not available in v4.04).

As of late 2017, we have begun adding support for J2534, and look forward to supporting hundreds of scantools from its implementation!

The Basics of ALDL Protocol

Not yet finished..

The Basics of OBD2 Protocol

Not yet finished..

What is a tuner locked ECU?

In the simplest terms, a tuner locked ECU is an ECU with a custom password. Without entering the correct password, you cannot get access to read or write a new tune.

For a more detailed explanation, please checkout our detailed explanation here!

What is a bricked ECU?

Sometimes things don’t go to plan while tuning/updating an ECU, which can cause a corrupt flash that results in a non responsive ECU.

For more information about what causes bricked ECUs, and how to repair them, please checkout our dedicated information page.