OBD-2 Anlyser not communicating with the PC

[jseamons]

I have built the kit but cannot get it to respond to the first request from the PC.The 5V supply is ok.The yellow Led will flash.The Xtal runs.Clock out/Baudin signal is present.Signals can be seen on TXD and RXD when the PC tries to connect.I have substituted the RS232 OBD-2 adaptor (Elektor 11/2002) and it will communicate under the same conditions.The software used is the OBD2 Scanmaster.
Help!
John Seamons

[bulent]

Hello

the mobydic communicates with PC only when

1.) no protocol found ( after search time ca. 30 sec.) yellow led blink with 3 sec interval

2.) succefully connected to a car ( green led on )

best regards
Bülent

[geoffn]

I also am having problems getting it to work – it doesn’t talk properly to the pc.

The car is a 2003 Honda Accord and when the OBD cable is connected to the car the green led comes on within 2 seconds. However the yellow led settles to a slow flash (3sec on, 3sec off).

Running Scantool v1.08 and selecting SENSOR DATA the pc reports “Device not Responding” in a dialogue box with OK CONFIGURE PORT IGNORE option buttons.
Clicking on OK – the yellow led changes to solidly on for about 15 seconds, then the pc shows the Device not Responding box again and the yellow led flashes slowly again.
Clicking IGNORE makes the yellow led stay on continuously.

Thinking this may be a RS232 problem I’ve checked the MAX232 by substitution and ‘scoped the signals to/from the pc. Good levels (+/-7V) are seen here.
The COM port is configured as 9600baud, 8bits, parity=none, 1stop bit, flow control=none.
The microcontroller xtal is running correctly at 16MHz.


To check what is going on, I arranged to monitor the RS232 signals with another pc running Hyperterminal and just connecting its Rx data line to the point to be monitored.
Monitoring the pc Tx line (running Scantool) shows that when selecting READ CODES, it sends 0101. The OBD analyser replies with a character which is ASCII 6. (Word won’t reproduce it).

If I click on the RESET CHIP button, the pc sends atz, 010E, 010B, 0110, 0103, 0111, 010C, etc.
After each character, the analyser replies only with the ASCII 6 character.

Connecting the analyser to a pc running Hyperterminal does exactly the same as above.
The analyser only ever replies with this same character.

Is this a faulty micro or just that it doesn't work on this car? What happens when the unit is connected to a model of car that is now known not to work correctly?

Geoff

[bulent]

Hello

I believe you are trying the software for ELM :laugh no 1.08 exists for mobydic). As we have no such commands as you have described .
to be sure please take our mobyplus software and try to start with this . If your car is diesel before 2003 you have maybe no OBD compliance.
please let me know the results

best regards
Bülent

[geoffn]

Thanks Bülent for your advice. I downloaded the Mobytester Plus program and it worked straight away with the yellow led settling to a fast flash at about 3Hz. Phew! The amount of time I spent looking for a hardware fault.
I had assumed that the Scantool program would work with this as www.scantool.net is shown in the 'links' info box in the article.
I had also tried the mOByDic Computer Interface beta 1.2 and OBD-2 Vehicle Explorer ScanToolBrowser Version 1.25, neither of which work with this unit.

The Honda Accord (petrol) can be added to the list of compatible cars. It shows as ISO9141-2

Thanks again Bülent.

Geoff

[tig124]

hello I am also having probems with getting the OBD to work, am getting the same problems!. Where do I get the mobyplus software from?

Thanks in advance

[bulent]

hello I am also having probems with getting the OBD to work, am getting the same problems!. Where do I get the mobyplus software from?

Thanks in advance

you find this software under

www.ozenelektronik.com

best regards
Bülent