Parasitic Current Drain 140ma Drops To 50ma With Obd Fuse Removed

Mybikes a cx500 · July 21, 2015

Seems like I got the basics in the title, after a weeks holiday I came back to a flat Battery, it is 4 years old, so perhaps past its best, but I investigated and there is a 140ma drain with the car locked and alarmed, and left for 20 minutes with the bonnet lock closed with a screwdriver, but the bonnet up.

Pulling fuses makes no difference except the OBD fuse, which drops the drain to a more reasonable 50ma.

I also get a few beeps from somewhere in the engine compartment when I pull this fuse.

So what is on the other end of the OBD fuse? I assume an OBD cpu, I will start looking this up, but anyone who has been here before, I'd be glad of any assistance

Zotto · July 21, 2015

Have you something connected to OBD plug ?

Mybikes a cx500 · July 21, 2015

Have you something connected to OBD plug ?

That's such a good question I went out and double checked, but no, nothing connected. I do have LPG, I wonder if that's got anything to do with it.

Checked again this morning and the drain is only 80ma, still a bit high

Clunkfish · July 21, 2015

Bit of a long shot, but do you have a USB or similar charging cable connected via the cigarette lighter socket? I had a big current leak from one of these even when the cable wasn't connected to anything, just plugged in at the supply end. I guess I'm thinking that the OBD and cigarette lighter might be on the same circuit....? Sorry if it's a red herring!

plexus914 · July 22, 2015

attached PDF is for 96 model. Check page 4 (79)

7. 5A / OBD- II

IG1 connector = COWL WIRE AND COWL NO. 2 WIRE (NEAR THE INSTRUMENT PANEL J/B)

1996 engine loom.pdf

Mybikes a cx500 · July 22, 2015

Bit of a long shot, but do you have a USB or similar charging cable connected via the cigarette lighter socket? I had a big current leak from one of these even when the cable wasn't connected to anything, just plugged in at the supply end. I guess I'm thinking that the OBD and cigarette lighter might be on the same circuit....? Sorry if it's a red herring!

I usually do, but not at the moment, and the cig lighters are wired to be on with ign. I do have a Parrot hands-free kit, wired into the amp under the seat

Mybikes a cx500 · July 22, 2015

attached PDF is for 96 model. Check page 4 (79)

7. 5A / OBD- II

IG1 connector = COWL WIRE AND COWL NO. 2 WIRE (NEAR THE INSTRUMENT PANEL J/B)

Brilliant stuff, so that fuse feeds the OBD connector, but when I unplug it , something beeps a complaint, so it does other stuff too, or its shorted to something. I will chase this IG1 connector