kittmaster

She has an 08 with 200K on the clock. Recently had the service jock "clear up" a noise which was the rotor backing plate basically crumbling and grinding in the rotor assembly (rusted and rot, thanks New England salt). Fast forward a few weeks to now, we are starting to see this code... I pull the tire... and sure enough, the wheel sensor connector and its mounting point is rotted off and "bouncing around" but no physical damage that I can see or cuts. I used my launch ODBII to clear the codes... and carry on...

There are no codes when I drive it... ever. However, the ABS, TC, and AH lights come on after the key cycle..... but not every time. Sometimes I can drive it several trips... no issues...i.e. turn the key, no codes.

One real random WTF was... I went to see a doc for an appointment... I got there... turned off the car... restarted it... twice... NO codes.... go into appointment.... lasts about an hour... come back out... turn key....******* codes are on... WTF??

So I put the tool in data stream mode and monitor the wheel sensor for the entire ride home... about 10 miles... the sensor didn't drop once... showed wheel speed all the way home... no issues, no data loss.

There are no other codes, just the -00 saying open or shorted..... which would mean the data would go to ZERO and I never saw that.....at all during a 10 mile rough road trip.... and I never get a code actively when driving it... only when I turn the key on startup.

Could a weak battery cause any of this? I do see the battery drop to around 9 volts when I key start it on the device.......doesn't mean it can't go lower... but I've never seen something like this......low battery that trips codes in a module???

Any ideas? I'm hard pressed to think that the module is bad at this point as I never get a code during drive mode.

Thx.

Patsgarage

If there was no damage to that sensor previously I would buy into the low voltage theory, but that should also throw other codes as well. Even though there is no visible damage to the wiring and connectors I would still lean in that direction first. A quick search on Rockauto shows sensors for ~$25, I would try that before anything else.

kittmaster

It is interesting, I charged the battery for 10 hours on a 10 amp charge.... have been on multiple trips since.... hasn't tripped (knock on wood).

I think one of the conditions was a voltage check... but my god... what a stupid thing to do... chasing a problem that may not exist.

I checked, the battery is 4 years old.... so not really in bad shape.... but surely the vehicle isn't used as much as when I bought it...

It's a wait and see I guess...

kittmaster

On the first attempt of this, I charged the battery 12 hours @10 amps. No codes popped since... So I said screw it.... left it on the 10 amp charge for 24 hours.... been running ever since... not a single code since.

Very strange... I've changed the battery in this more than once... it never fired codes due to a low voltage... so maybe the module is getting old and the caps drying out... and low voltage is triggering codes if the voltage doesn't ramp up fast enough.

Very very strange... not changing a brake module out for this... will let it ride and see how it goes... the plandemic really caused it to sit around a lot, and the battery was replaced 4/19 so it's 4 years old with local driving and little real charging to keep the battery proper.

So for now, I guess it's "solved"... if it comes back I'll update this thread.... thanks for the response.

Chris

Patsgarage

Interesting. I would have bet that low voltage would have popped other codes, but it looks like that was your issue.