Just noticed this DIAGNOSIS Port/Socket on the SUV, which sits next to the OBDII port - I have no idea about why I have not noticed it for all these years.




Is there a reader device for DIY on the market? Is there a signal specifications sheet for the labeled pins?

 

The current day standard is OBDII which was mandated in '95 in USA. Before that manufacturers had their proprietary ports. Toyota/Lexus has such ports and you are identifying one of them. In the engine compartment there is another diagnostic port which is used for ABS. Some of these ports use a wire to short two pins and count number of flashes in the cluster.

You may find more details and dedicated test boxes in the service manual. Since this stuff is proprietary, commercially available readers did not hit the market and Lexus/Toyota dealers are the only locations which own them.

Salim

 

Thank you salimshah, for sharing your expert insights.

 

Definitely not an expert.

There is a black rectangular port in the engine bay roughly 2.75" x 3/4" with "diagnostic" embossed on it. I used that to extract ABS codes which I was unable to get with OBDII. I attributed it to my cheap tester. I never had to read airbag codes or even the need of reseting it. The control of ABS valves for bleeding is with these proprietary diagnostic ports.

Salim