wwnf

I've been having a parasitic battery drain/gremlin lately and decided to hook the Dc Amp meter up and try to locate it. After checking all the smaller fuses I couldn't get the draw under 90-110mA so I started pulling the Maxi fuses. The engine fuse box maxi fuse 53 ABS/ELEC (Anti-lock brakes) when pulled dropped the draw down to 20mA so I found the drain.

Now I'm stuck, I don't know how to proceed. What can be the drain with the ABS system? How do I narrow down more or fix?

Thanks

98 Corvette Coupe

BLOWNBLUEZ06

You'll need a schematic from here. With that, you can begin pulling plugs on wire junctions and equipment that runs off that fuse until you again see the draw disappear. You might want to put the fuse back in and watch your meter while you wiggle main harnesses behind the engine and along the frame. If you see it jump up or down, you have found the area of your problem.

Bill Dearborn

If you have real time dampening shocks the draw could also come from the ESC module which gets its power feed from the same fuse. In the ABS system that fuse is used to power the solenoid valves of the BPMV. There could be some high resistance short in to ground on that line somewhere but it seems if a short was in one of the solenoids it would draw a lot more current than what you are seeing. Do you have active handling on the car? Do you have a front mounted or rear mounted EBTCM?

Bill

wwnf

I don't have any diagrams but I'll look for some but in the mean time I'll do some harness vibration tests and see if I can find anything.

Thanks again.

wwnf

Looks like I'm going to need to find a schematic and put the car up on ramps. I tried just disconnecting wheels sensors and nothing changed. Unplugged the harness from the ABS brake line hub just behind the radiator fan and the voltage dropped to 0.02 so I guess it's something in that harness. I should be able to find time over this long weekend.

Thanks

wwnf

Wasn't getting any codes so I purged all the codes and drove around came back, and now I got C1241, MagnaSteer, soon I'll get back under the car and check that circuit out. I feel like i"m getting closer.

Thanks again

wwnf

Now I'm getting codes for the wheels sensors along with c1255, could a bad EBCM cause a battery drain? The ground near the battery is rusty so I'm going to try to clean that up but everything else looked good. I'm thinking I'm in need of a new EBCM. Wish I could tell 100% before I spent the money on a new one.

wwnf

Anytime I reset the TCS codes the C1241 (MagnaSteer) returns immediately and when I have this disconnected I still have the battery drain so I think something is shorted out in the EBCM so I ordered a new one.

wwnf

Finally got a chance to replace the EBCM Gm ACDelco Part # 9367071 and everything works great again. No more battery drain, amps DC drop to 0.02 when car goes into sleep mode. No more MagnaSteer codes, woo hoo.

The only problem I had with removing the old EBCM was the 5th bolt that is also used with the rubber mount stayed hidden until I re-read some posts. Had to remove the rubber mount to get to the bolt.

Thanks again.