Grounding issue in Jimny. Any help appreciated :)

Hi all. Just bought a 2006 Suzuki Jimny. Drove for 30 minutes, petrol was very low, filled up entire tank. Drove another 45 minutes and car lost all power and broke down. Both recovery guys couldn't get it started. Car would turn over but wouldn't start. When I got it back home still wouldn't start. My mate plugged in ODB2 reader and saw it had a P0327 code "Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)". After clearing the code it started immediately. Car runs but when you unplug ODB2 reader it will die again within a minute and the P0327 code comes back and then the car wont start again until code is cleared. If anyone has any ideas I would be eternally grateful!

Update: Looks like a grounding issue. Tested by taking an old ODB2 port and soldering up the grounding connections and worked fine. Any suggestions on how we should go around fixing?

Mine had a similar issue but without the fault codes. Would not run without the OBD2 connected. I got the fault from disconnecting the OBD reader while engine was running. Smoke came out from something in the dash or ECU area and after that the car would not run withiut OBD2 connected.

Changed the dashboard instrument cluster as something was off in there. Most likely shorted something and the dashboard electronics got toasted.

Can't remember what/who in here made me buy the new to me cluster from a scrapper, but took a while before I figured it out.
Haven't had any such problems since.

I Remember now there is a diode inside the dashboard wiring somewhere (according to the wiring diagram) and those are often there for protection against shorting. I never found it to test it while i looked for toasted wires or bad connections. There is a few grounding points in there and wires to and from those was checked before I did the cluster.

Pin 5 is the ECU signal ground and Pin 4 is chassis, so if the OBD2 reader is doing anything with the ground it is connecting pin 4 to pin 5.

If this is the case and this is what makes the car run then it looks like a fault with the ECU earth, since normally pins 4 and 5 are not connected.

I would check the wiring diagram for the ECU ground as the wiring to the OBD2 socket is not really big enough to provide a main earth for the ECU.
I would suggest that the OBD2 socket is the wrong place to make the ground connection, you might risk too much current going through the socket wiring and that’s when the cabling will burn out.

Robin