Parking sensor issues after battery disconnect

[Red_Corolla]

So, I've made a bit of a fool of myself by briefly disconnecting my Battery just because I wanted to get some parasitic drain figures. This has ended up causing me problems - curiosity killed the cat!

I only had the earth lead off for a few seconds (this is actually correct procedure before recharging, according to the manual) and since reconnecting I have the faults, "PKSB unavailable" and "Parking assist unavailable" showing alternately on the dashboard.

I've connected with Carista and cleared 2x fault codes pertaining to lost communication, as you might expect when power has been lost. There are no remaining fault codes showing up and yet the parking assist is still upset. After a bit of initial research, I fear the car might have to be taken through a calibration procedure using factory level diagnostics in order to cure this. 😔

Does anyone have any advice for me, please (apart from the obvious stop meddling)? Is it feasible to buy a cheap interface dongle and sort it out by buying short term access to the techstream software? Or should I just go cap-in-hand to the dealer and let it be a lesson to myself? I'm worried that approach could be costly! Although I know I'm an idiot, I still feel disappointed to be in this position after a simple Battery disconnect.

[Mooly]

Try disconnecting the Battery again for an hour or two might be one option to try. A few seconds of disconnect and perhaps with 'dithery fingers' (its a technical term, don't be offended 🙂 ) as you tried to perhaps measure current draw could spike something and put some system into an invalid state.

If it ends up needing dealer attention then just be honest and say you disconnected the Battery to charge it and the fault appeared afterward. If the manual says to disconnect the Battery for charging then point out that you did just that as instructed. The dealer will probably view it as yet another Hybrid with 'battery issues' and report the problem accordingly on any warranty claim.

[Cyker]

If it said malfunction it would be worth a trip to the dealer, but as is just says unavailable I think it's just the parking sensors have lost calibration.

I think if you just use the car for a bit it should recalibrate itself...?

Also make sure there isn't a load of dead insects or guck splattered over the sensors or something! Or just give them all a clean anyway...

[Red_Corolla]

Cheers gents, I do have dithery fingers but that wasn't quite how it panned out. I had the meter hooked up nicely without interrupting anything and the car fooled by latching the tailgate lock with a screwdriver, so boot lights were off and current draw around 60mA. It was when I started moving the meter onto the floor ready to lock the car up that I pulled a crocodile clip off and broke the connection! Still a clumsy mistake, when all is said and done, but I don't feel it should have caused me this much grief. Of course, the current draw went thorough the roof once I reconnected it and then I turned on the car and discovered the fault. As you can imagine, I was no longer in a mood to continue with my daft experiments after that point.

@Cyker the car is clean enough and I'm sure this is not a coincidence - it's the Battery disconnect that's upset it. I will take your good advice of using the car for a while and hoping it sorts itself out as there's nothing to lose by doing that. If it ends up going to the dealer then I will have to own up to disconnecting the Battery, but I'll have to add a white lie by saying it was flat as that's really the only reasonable excuse for disconnecting it.

[Cyker]

To be honest just disconnecting the Battery for a bit shouldn't cause a major system malfunction that requires dealer attention - If it did all these people with their batteries going flat over lockdown would have sparked a major backlash!

In the manual for my Yaris, it does more or less say that if you get that error as soon as you turn the car on, just make sure the sensors are clean and drive around for a while normally and it'll go away eventually, so I think you're okay!!

[TonyHSD]

I think the advice to disconnect again and leave it disconnected for at least 20 min or even longer may do the trick. Disconnect and immediately reconnect may have caused some sort of power surging that has upset the systems in question. There have been so many complaints about dead batteries in Corolla and non about faults afterwards, therefore I also think Mooly is correct. 
Good luck 👍

[Red_Corolla]

Thank you all for your calm and sensible advice. I was having a bit of a panic there, but pleased to report all is well now.

I tried disconnecting the Battery for a full hour. It made no difference except the clock reset (but quickly corrected itself). It even maintained the radio presets. But the parking assist error also still remained.

At that point, I decided on a short drive as a latch ditch attempt to resolve it before it started to cause me lost sleep. The error messages cleared up within the first minute and I was reassured to hear the parking sensors working once more when I returned and backed up to the garage. 😃 Still feeling rather daft but the anxiety has been replaced by relief. 😆

[Mooly]

Excellent news. Thanks for the update and I'm pleased to hear its all good now.

[Rhysm]

Late to the thread, after disconnecting Battery or parking sensors components, the car needs to be driven above 30mph, for less than a minute to re calibrate, cars come from factory with this but is always clears when they fuel them up 

[UncleZen]

Even later to this thread...

The exact same thing happened when I changed the Battery in my CHR, fortunately I found this article and true enough the warning cleared after about 300 yards.