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Car experiments

2010-03-29: Never enough electronics

The car

The car in question is a Saab 9-3 Aero MY2001 (B205R engine) that I got this summer. It's a fun car not only because it drives well but also because there's so much information out there on its engine control unit Trionic 7. I don't have any ambitions of chip-tuning it (at the moment) but it's nice to know that I could.

Car computer take I: CAN interface and display

The car is equipped with a Olimex AVR-CAN board mounted behind a panel in the trunk. It is connected to battery power and the CAN I-bus through the CD changer harness. One of the serial ports on the AVR-CAN board is connected to a 4x20 VFD display on top of the dashboard.

On the display I get vehicle information such as current speed, tank level, fuel consumption, atmospheric pressure, inside temperature, and engine parameters such as RPM, MAP, MAF, inlet temperature, knock and misfire counts per cylinder. The computer is controlled with the steering-wheel buttons.

at90can128 AVR firmware source

MP3 player input

The AVR-CAN board activates the CD changer input on the standard Saab head unit. A mp3 player can then be connected through a simple OP-amp amplifier to the back of the head unit.

Some good links

Reverse-Engineering the Saab 9-3 Instrumentation Bus (I-BUS)
Trionic 7 mapping
ECUProject


This page was last updated: Sat Apr 10 15:07:50 2010


Jonas Norling <norling@lysator.liu.se>
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