Diagnostic Versions and Communication Methods

Diagnostic versions and communication methods

General
Since the end of the 1980s, the control module's diagnosis has developed from detecting simple problems and storing a small amount of information to including more complicated tests and checks.
Today a large amount of information can be read out both about the detected problem as well as parameters from the control module's input and output signals.
The following accounts for the main principles for this development.

Volvo Diagnostics I - first version




A Volvo standard was introduced (Volvo Diagnostics I) 1988, which means diagnosis of several on-board systems (On Board Diagnostic).
This Volvo Diagnostics included:
- Store problem indicators (diagnostic trouble codes) for various components as well as delete them (check function 1).
- Confirmation of activating components or functions (check function 2).
- Cyclic activation of components/functions (check function 3).
A diagnostic tool (diagnostic socket with light-emitting diode) was located in the engine compartment for reading out a Volvo Diagnosis from the various control modules.
Volvo Diagnostics, the first version is found on, e.g., fuel control system LH 2.4 and ignition system EZ 116K for model 240 and 740.

Volvo Diagnostics I - second version
Volvo Diagnostics, the second version, was introduced in 1991 meant that additional services were made available, such as:
- Possibility to control transfer rate for data between the control module and the diagnostic socket.
- Individual activation of components/functions (check function 4).
- Read in and out signals (check function 5), where every value is represented by a three-digit code.
- Enter data (check function 6), where you could enter data via three-digit codes.
Services are introduced to varying extent on the different control modules.
The diagnostic socket with light-emitting diode is used to read out Volvo Diagnostics from the various control modules.
The tool Volvo Diagnostic Key and then Volvo System Tester were introduced to make communication easier with the control module.
Volvo Diagnostics, the second version is found on, e.g., Transmission control module (TCM)a AW 30-40/43 in model 960 and AW 50-42 in model 850.
For further information on the diagnostic socket and its functions, see service information for each system.

Non-standardized serial communication
As a supplement to Volvo Diagnostics - first and second version, the supplier of engine management systems developed their own diagnostic and communication methods (On Board Diagnostic). These were introduced during 1991/92.
These serial* communication methods were supplier-specific and varied a lot between systems. To communicate quickly and directly with control modules was a pre-condition for developing the control system and opened for new possibilities.
The access to more information about the detected problem as well as the possibility to, e.g., quickly read out parameters, enabled improvement of troubleshooting methods. Therefore, these communication methods were used by the workshops' diagnostics tools.
The cable in the vehicle used for this serial communication is connected to the diagnostic socket in the engine compartment and is the same one used for Volvo Diagnostics, first and second version.

Included functions are, among others:
- Reading out and erasing diagnostic trouble codes.
- Reading off frozen values.
- Reading off values of signals such as coolant temperature, voltage on heated oxygen sensor, etc.
- Activating components and functions.
- Programming of customer parameters and functions.
- Calibration of functions.
- Resetting of adaptations.
The tool Volvo System Tester was developed to make communication easier with the control module.
Non-standardized serial communication was introduced on engine management system Motronic 1.8 in model 960 and engine management system Fenix 5.2, Motronic 4.3, and LH3.2/EZ129K in model 850.
* Serial means that the information is sent as a series of signals in the form pulse trains (= series of pulses) via a cable between the tool and control module.

Volvo Diagnostics II - first version




Volvo Diagnostics II - first version was a new Volvo standard introduced in 1996. This meant that control modules communicated serially in the same way, and that diagnostic functions in the different systems were designed in a similar manner.
The communication cable in the vehicle used for this communication is common to all control modules in question. The control modules are connected to the same connection in the diagnostic socket (pin 7).
The diagnostic socket is located in the passenger compartment and for certain markets it is common with the diagnostics system OBD II.

Volvo Diagnostics II, first version, was introduced in 1996 on, among others:
- Engine management system Motronic 4.4
- Automatic transmission AW 50 42/AW 30 40/43
- Control module Airbag SRS6.2
- Immobilizer
- Control module Brakes ABS 850
- Combined instrument panel 850
- Power seat 850/960
- and was gradually introduced for additional systems and car models.
For certain models, the diagnostics tool for this diagnosis is still Volvo System Tester (car models from and incl. model year 1998 as well as certain systems for model year 1999).
The diagnostics tool VIDA, now replacing VADIS, is used for car models of model year 1999 and later.

Volvo Diagnostics II - second version




Volvo Diagnostics II - second version was introduced in 1999 and is a development of the first version. The major difference is that communication between the diagnostics tool and the control modules takes place via CAN-communication instead of on a communication cable.
The control modules also communicate with each other to exchange information on the CAN-net instead of via separate cables between the control modules.
This version introduced the possibility to download software to the control modules.
With the introduction of this version, the rate in the low-speed network was (LS CAN) 125 kbit/s and the rate in the low-speed network was (HS CAN) 250 kbit/s. Depending on model and model year, the speed of the network has increased with time.
For further information about CAN, see Design and Function, CAN-net as well as Design and Function, Downloading Software.
Volvo Diagnostics II, second version, was introduced in model S80/S60/V70 (00-)/V70 XC (01-)/XC70/XC90 model year 1999- as well as S70/V70 (-00)/V70 XC (-00)/C70 for model year 1999 and thereafter in future models.
The diagnostics tool VIDA, now replacing VADIS, is used for car models of model year 1999 and later.

Generic Global Diagnostics (GGD)




Generic Global Diagnostics (GGD) is a mutually developed diagnostics concept within the Ford company.
Communication and services are similar to Volvo Diagnostics II - first version. Communication between the diagnostics tool and control modules takes place via CAN-communication. The services that can be performed are similar.
Designation of trouble codes adheres to standard ISO/DIS 15031-6.4 and consist of a letter and six characters.
The control modules also communicate on the CAN-net with each other to exchange information.
It is also possible to download other software to the control modules.
Volvo Diagnostics, fifth version, was introduced in model XC90 model year 2005 with engine B8444S (only high-speed network) and then in model S80 (07-).
The diagnostics tool VIDA, now replacing VADIS, is used for car models of model year 2005 and later.