ELM327 USB OBDII Scanner (cheap silver ones)

[stevesey]

Got around to ordering one of those cheap silver £20 ELM327 units the other week. No sign of a real ELM327 chip inside - some 16xxx series PIC instead. However just connected it up and all works fine - monitoring pin 4 of the 38pin socket on my car.

Now planning to wire a perment connection from the 38 pin thorugh to a OBDII connector to make life easlier (and allow logging on the move). If the Rad block experiment continues - I should be able to monitor the MAF/Throttle position etc with/without the block to see the effect on engine load.

At present I'm only monitoring the K-line of the ECU - wondering about adding CAN bus to the connector - does anyone know a good place to pick CAN H and CAN L up from?

 

[Dieselman]

The ignition switch would be convenient, but does that CAN take diagnostic information or just supply stop/Go signals to the various units.

Tell us more about the ELM jobbie, is it reading proprietory Merc codes or OBDII, in which case all you needed was an OBDII scanner and connector, which is what I think you need..

 

[stevesey]

Tell us more about the ELM jobbie, is it reading proprietory Merc codes or OBDII, in which case all you needed was an OBDII scanner and connector, which is what I think you need..

ELM jobbie (mine was £20) is only an interface really it's the PC software that does the real work. I did try a very simple DIY interface - but was having trouble waking the ECU up and getting it to talk (plus no laptop with RS232). Might try this again sometime now I've got the ELM talking.

Currently I've tested with scantool.net and EasyOBDII which are just reading the OBDII stuff. The C# code to read stuff is faily simple, so I'm planning on having a fish on the other pins of the 38 pin to see if I can read those - I know Richard managed to read the gearbox codes in freediag. Also I was planning to check all the OBDII fields actually returned by the Merc to see if there are others that the above software is not showing me. Ultimately I'd like to have a go at a full digital dash (on a laptop initially).

N.B When I ordered I wasn't aware - but this is a chinese copy and not a genuine ELM stuff. It works though.