CharBaby

I have known this for some time now and it may have even been discussed on this or other forums but, I would like to share my information with all of you. For those of you who don't know why your time/clock resets to 01:00 when starting a cold engine, this is WHY!

I believe that this is Toyota/Lexus' way of telling the TECH's that there is a battery issue. The time doesn't go back to 12:00 as one would think, it resets to 1:00 or 01:00. And the same with the inside temp. Doesn't reset to "COLD" but to 75 deg's on the dash screen.

Regarding the information from the center screen(Blue or Black Dash Screen) in the upper center console between the HVAC Vents:

*When your clock resets to 01:00 after a cold start AND/OR your climate temperature resets from HOT to 75 deg F, this means that you have a battery that is weak or has a bad cell or even a bad ground in your wiring system.

I have noticed this in my particular '01 RX-300 since "NEW". My OE battery lasted over 8 years but, I replaced it anyway as I had suspected it was going bad and winter was approaching at that time. Turns out, it had a bad cell even though, the engine would still started even in the ))COLD(( winter mornings. But, the information screen(Time/Temp) would constantly reset to 1:00/75 deg respectively!

**In my particular case, I believe that I must have a bad ground as this has been happening since "NEW" and with all the batteries that I have now installed(3...OE & 2 others). My current battery is now 1 year old and is a AutoCraft GOLD, as was my last one(a.k.a. AutoCraft Platinum). And the current battery is strong with no known issues(load tested). The Dash Screen(as mentioned above) in now resetting in both areas(Time & insideTemp/climate control)

***Bit of history...With each of the first 2 batteries(OE & Platinum), during a load test, one(1) cell was SHOT in both batteries! This(IMHO) could be from the "suspected" bad ground.

But for those of you who didn't know why the clock and/or temp would reset, this is why!

Hope I've explained this well and I just wanted to get this information out there!

CB

****Oh, before I forget. I have since new, have gotten some very random CEL's pop up with the codes pertaining to A/F sensors. But, after resetting the ECU. the CEL would disappear and not come back for up to a year or so!

*****Another Strange Thing:
Any time I have done a battery disconnect for maintenance purposes, I will get a CEL after the reconnection of the battery and 3 engine startups...Again, CEL's pertaining to the A/F sensors but, another reset(whether doing another battery disconnect or pulling the ECU-B/EFI fuses, and the CEL goes away for what seems like...for good or (about 1 year or so)!

IMHO^^^ I believe that a possible bad ground is the reason for my CEL's also!

That's all!

2KHarrier

Hmm.. interesting. I haven't experienced this, but it's good to know what to look for, especially when the battery condition is so important.

salimshah

My 2c:

When the battery is weak and the starter kicks in the voltage drops .. and once it falls below what the clock needs to keep running it resets(12am)


As far as ECU, it takes input from sensors. The normal (expected good) value requires good supply (charged battery).

Salim

fastnoypi

it is very possible the clock time might be a code. Certain cars, have ways of tech diagnosis for example blinking CEL sequences, that could tell a tech to look for a particular condition.

I'll keep this observation in mind if i get into a suspected damaged cell/low battery situation.

CharBaby

Strange! Even when I do a battery disconnect for either, maintenance reasons OR, to replace the battery, my clock is reset to 1:00 not 12:00. Hmmmm!

Our '01 RX has had the OE battery and 2 others in 13 years. The current battery, I installed Jan-Feb 2014(1 yr old). That's about right for it's age(14 yrs old now).

This is why I am thinking that I may have a bad ground cable(or Positive cable), IDK!

tllee

My clock also reset to 1:00 whenever I disconnect my battery. Never pay attention to it until you mentioned it. Mine is '02. I think that may be a factory set up and can be changed by dealer( they may have pass code to do that). I remember that I saw something on user manual which state some control can be changed if we bring it back to dealer. So you may try to call your dealer to see what they say. Just my guess.

RX469

iTrader: (1)

Interesting info.