FreeSSM (devel) - Documentation/Help

Contents

A.) Preface

B.) Frequently Asked Questions (FAQ)

C.) Abbreviations

A.) Preface

The use of this software is at your own risk. The author is not liable for any malfunctions or damages that may be caused directly or indirectly by usage of this software. Both depend on the used hardware (interface), too.
While driving the car, the software should NEVER BE OPERATED BY THE DRIVER ! Always ensure that the interface cable does not affect/compromise the vehicle operation !

B.) Frequently Asked Questions (FAQ)

1.) What kind of interface do I need ?

2.) Which vehicle models are supported ?

3.) Which control units are supported ?

3a.) Why can I connect to the engine's control unit but not to the transmission's control unit ?

3b.) Why are the other control units not supported ?

4.) Why does FreeSSM not show the control unit spare part number or informations about the software version ?

5.) Why does the engine control unit support OBD2, but the transmission control unit doesn't ?

6.) Why does the engine control unit not detect the Cruise Control although my car is equipped with one ?

7.) Why does FreeSSM display different titles/descriptions for some Data Trouble Codes ?

8.) What does "non-permanent" mean in reference to the Adjustment Values ?

9.) What is the "test mode connector" and where can it be found ?

10.) Why does the Actuator test not work for some components ?

11.) What happens when clearing the control unit's memory ?

12.) What's the difference between "Clear Memory" and "Clear Memory 2" for the transmission control unit ?

13.) Why does "Clear Memory" not clear all Diagnostic Codes in some cases ?

14.) Does FreeSSM use/support the CAN-Bus ?

15.) Will development of FreeSSM go on ?

1.) What kind of interface do I need ?

The software works with all ISO-9141-2-/ISO-14230-1-compliant (K/L- and KK/L-) interfaces, that serve as simple voltage level converters ("Dump"-interface) or have a "pass-through"-mode.
The interface must be selectable through a serial port, which also includes USB-interfaces whose driver provides a virtual serial port (e.g. interfaces with FTDI-USB-chip).
This is a (incomplete) list of interfaces that should work with FreeSSM (no guarantee !):
- all interfaces that work with VW-Tool and VAG-COM up to version 311.3 (409)
- openPort-interface 1.2/1.3 (not 2.0 !)
- interfaces with AGV2055, AGV3000, AGV3001, AGV3100, AGV4000, AGV4500 chipset that provide a switch to activate the "transit mode" (e.g. OBD-Diag®-interfaces)
- "Jeff Noxons" interface (-design)
- "Andy Whitakkers" interface (-design)
Interfaces with ELM-chip (ELM320, ELM322, ELM323, ELM327) will not work, because they use a fixed AT-command-set which is not compatible with the SUBARU®-specific protocol.

2.) Which vehicle models are supported ?

The software supports the models Legacy®/Liberty®/Outback®/Baja®, Impreza® (incl. WRX + STi), Forester®, Exiga® and Tribeca® starting with model year 1999 up to model year 2009.
Model year 2010 is already supported, too, but some Measuring Blocks may be missing and some Diagnostic Codes may not be displayed as plaintext.
Vehicles up to model year 1998 as well as the models SVX®, Justy®, Libero® and Vivio® are not supported.
The model years 1999+2000 must be regarded as transition period. According to present obersvations (european models), access to the engine control unit of the models Legacy®/Liberty®/Outback®/Baja® is already possible since model year 1999, while most of the Impreza®-models and a few of the Foresters® are supported from model year 2000 on.
Transmission control units are not supported before model year 2000, in most cases support starts with model year 2001.
It is useful to take a look at the diagnostic connector: if pin 7 is available, at least the engine control unit should be available.
From model year 2001 on, both control units should be supported.

3.) Which control units are supported ?

The software currently provides access to the engine and transmission control units.

3a.) Why can I connect to the engine's control unit but not to the transmission's control unit ?

Depending on model and model year, it is possible that the engine controller already uses the new (supported) protocol while the transmission control unit still uses the old (unsupported) protocol.

3b.) Why are the other control units not supported ?

Because they use different communication protocols and are also connected through other diagnostic lines with different electric attributes.

4.) Why does FreeSSM not show the control unit spare part number or informations about the software version ?

The only identification information provided by the SUBARU®-diagnostic-protocol is the ROM-ID, which is displayed by FreeSSM.
The correlation between the ROM-ID and part numbers or software versions is ambigous. Control units with identical ROM-IDs can have different part numbers and may be equipped with different software versions.

5.) Why does the engine control unit support OBD2, but the transmission control unit doesn't ?

OBD2 is a "functional" system that incorporates informations and functionalites from different control units. The FreeSSM "OBD2-System"-information only states, that the corresponding control unit takes part in this system. In older vehicles, only the engine controller is involved in the OBD2-system.

6.) Why does the engine control unit not detect the Cruise Control although my car is equipped with one ?

In older vehicles (without electronic throttle control), the Cruise Control is a separate system that is controlled by it's own control unit.

7.) Why does FreeSSM display different titles/descriptions for some Data Trouble Codes ?

Some of the old 2-digit-SUBARU®-DTCs (control units without OBD2-support) are used multiple times with different meanings.
FreeSSM can distinguish them and diplays the right title/description.

8.) What does "non-permanent" mean in reference to the Adjustment Values ?

"Non-permanent" means, that all values are reset to default when disconnecting from power supply or clearing the control unit's memory.

9.) What is the "test mode connector" and where can it be found ?

The test mode connector is a pair of green 2-pin connectors, which are not connected at normal operation. When they are connected, the engine control unit (ECU) goes into a special operating mode (test mode). Several automatic test routines are running and special tests (like the actuator on/off test) can be performed.
Furthermore, the engine is operated with different parameters and usually parts of the body electric (e.g. central locking) are decommissioned. That's why the test mode conncetor is also known as "delivery mode connector".
It is always located in the area of the dashboard and the legroom, the exact position depends on the model.
The following positions apply to left-hand drive models:

| Model (type): | Model Year: | Position:
--- | --- | --- | ---
| Legacy/Liberty/Outback/Baja (BE/BH) | 1999-2003 | at the lower portion of instrument panel (driver’s side), at the side of the center console box
| Legacy/Liberty/Outback (BL/BP) | 2004-2009 | legroom, beneath the glove compartment
| Impreza (GC/GF) | 1993-2000 | upside behind the dashboard (driver's side)
| Impreza (GD/GG) | 2001-2007 | upside behind the dashboard (driver's side)
| Impreza (GH) | 2008+ | legroom, beneath the glove compartment
| Forester (SF) | 1998-2002 | upside behind the dashboard (driver's side)
| Forester (SG) | 2003-2008 | upside behind the dashboard (driver's side)
| Forester (SH) | 2009+ | legroom, beneath the glove compartment
| Tribeca (WX) | 2005+ | legroom, beneath the glove compartment

ATTENTION: connect or disconnect the test mode connector only when ignition is switched off !

10.) Why does the Actuator Test not work for some components ?

Not all of the selectable actuators are available in every vehicle. The SUBARU®-diagnostic-protocol only provides the information, if actuator tests are supported or not, but it doesn't provide any information about the available/testable actuators.
That's why FreeSSM always lists all known actuators.
If the selected actuator is not available, simply nothing will happen during the test.

11.) What happens when clearing the control unit's memory ?

All diagnostic codes are cleared (also see question 13 !) and all adaption values are reset to default.
For newer engine control units with electronic throttle control, the corresponding learning values are reset, too. This can result in unusual engine behavior for the first time after clearing the memory.
Therefore, it should not be done without a reason.

12.) What's the difference between "Clear Memory" and "Clear Memory 2" for the transmission control unit ?

"Clear Memory 2" includes "Clear Memory" and also clears all learning values of the transmission control.
This can result in unusual behavior of the transmission for the first time after clearing the memory.
Therefore, it should only be applied if a reset of the learning values is the goal !

13.) Why does "Clear Memory" not clear all Diagnostic Codes in some cases ?

There are two possible reasons:
a.) the problem/malfunction that caused the diagnostic code to be stored still exists (immediate redetection)
b.) on newer vehicles, some (emmission related) diagnostic codes can not be cleared at manufacturer level. They have to be cleared in the OBD2-system, for which an additional OBD2-Scantool is needed.
PLEASE NOTE: FreeSSM IS NO OBD2-Scantool !

14.) Does FreeSSM use/support the CAN-Bus ?

No, because it's not necessary. Of course, the newer vehicles are working with a CAN-Bus system, but it is not used for diagnostic purposes at manufacturer level or rather the communication between engine/transmission control unit and the diagnostic equipment.

15.) Will development of FreeSSM go on ?

That's the plan. The latest version is always available at http://freessm.berlios.de.

C.) Abbreviations

AAI | Air Assist Injector
ADA | Active Driving Assist
AET | AT Engine Torque request
ASV | Air Suction Valve
ATF | Automatic Transmission Fluid
AVCS | Active Valve Control System
AWD | All Wheel Drive
CPC | Canister Purge Control
CVT | Continuous Variable Transmission
DCCD | Drivers Control Center Differential
DTC | Diagnostic Trouble Code
EAM | Engine AT Masking
ECM | Electronic Control Module
EGR | Exhaust Gas Recirculation
ETC | Electronic Throttle Control
FICD | Fast Idle Control Device
FWD | Front Wheel Drive
ISC | Idle Speed Control
MIL | Malfunction Indicator Light
OCV | Oil flow Control solenoid Valve
OSV | Oil Switching solenoid Valve
PCU | Powertrain Control Unit
PCV | Positive Crankshaft Ventilation
TCM | Transmission Control Module
TCS | Traction Control System
TGV | Tumble Generator Valve
VDC | Vehicle Dynamics Control
VVL | Variable Valve Lift
VVT | Variable Valve Timing

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OBD-Diag is a trademark of Folker Stange
All other trademarks are property of Fuji Heavy Industries Ltd. or their respective owners.