MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: LozB on June 1, 2024, 19:26

Title: ABS light and battery drain
Post by: LozB on June 1, 2024, 19:26
Two new problems emerged today on our pre facelift MR2:

ABS light has come on.  We have just changed the discs and pads but it wasn't on before.  There is no fault code when we run a diagnostic.

Battery drain. The new battery keeps going flat.  It was replaced a few weeks ago along with a recon alternator and has been fine until today when we were road testing following installation of new brake disks, pads and pre loved rear callipers. Every time we switch engine off it needs a jump to restart. This happens even after driving for a few miles.  Very strange.

Coincidence or could these problems be related?

Any advice appreciated
Title: Re: ABS light and battery drain
Post by: Joesson on June 1, 2024, 20:47
@LozB

Iirc there is a "contact" on the brake pads that connects with whatever to signal pad wear at end of life.
Just maybe, for some reason, that is in permanent contact and not helping your situation.
Title: Re: ABS light and battery drain
Post by: Gaz mr-s on June 1, 2024, 21:18
You need to check alternator voltage at the battery.  On the basic info, it's not charging it.  However, if the battery voltage pre-jump start was really low, the alternator may not charge it.  I'd never experienced this, but did just recently.  If that's the case you need to parallel the battery with another so that a smart charger will be triggered.

I don't think the car has a brake pad warning.  The tang on the pads is a 'scraper' to give an audible warning.  I fear you have a sensor issue.  Someone will confirm, - I believe you'll need Toyota's Techstream to get diagnostic of it.
Title: Re: ABS light and battery drain
Post by: Topdownman on June 1, 2024, 22:21
I would take every wheel off and check the sensors are connected ok. I had the warning come on and it turned out to be a sensor was unplugged.

I seem to remember that there is a way to identify the problem by counting flashes of something but cant remember the details!
Title: Re: ABS light and battery drain
Post by: LozB on June 3, 2024, 00:13
Ok today we checked the alternator and confirmed working fine.  Battery was charged overnight and behaved fine today, but only driven a few miles so will see how it goes.

Also checked ABS sensors which all appear fine, albeit we found our front left calliper is sticking, binding the wheel slightly. Could this cause an ABS fault light?
Title: Re: ABS light and battery drain
Post by: Alex Knight on June 3, 2024, 19:18
Quote from: LozB on June  3, 2024, 00:13Also checked ABS sensors which all appear fine, albeit we found our front left calliper is sticking, binding the wheel slightly. Could this cause an ABS fault light?

No.
Title: Re: ABS light and battery drain
Post by: LozB on June 3, 2024, 20:20
Quote from: Alex Knight on June  3, 2024, 19:18No.
Oh dear. Any other suggestions?
Title: Re: ABS light and battery drain
Post by: fawtytoo on June 3, 2024, 21:49
Some cars (dunno about the '2) throw an ABS light if the brake lights don't work.
Title: Re: ABS light and battery drain
Post by: Alex Knight on June 3, 2024, 22:02
Quote from: LozB on June  3, 2024, 20:20Oh dear. Any other suggestions?

Yes, read the code(s) or get the code(s) read, and report back:

Title: Re: ABS light and battery drain
Post by: Topdownman on June 4, 2024, 08:05
Thanks Alex, that was what I couldnt remember!