Car Wash Caused Hybrid System Warning

[rachaelseven]

Originally Posted by maledyris

I've been trying to figure this out too. I don't think it will work. The problem is that the $300 cable lacks the ability to adjust voltages on specific pins. This is required for reprogramming as far as I understand (documentation is tricky to come by). I read the j2534 spec and it's pretty straightforward. Originally I thought I would buy a reasonably priced cable and make the dll interface myself. Sadly, I no longer think this is possible with a cable that lacks these capabilities...

You could well be right, I just don't know for sure. I thought the $300 ISO/CAN cable from Drew Tech was a J2534 programmer though, so I'm somewhat surprised. And it does come with drivers to connect it to Techstream, so it really seems like it should work. I suspect a phone call to Drew Tech would clear it up for certain - their tech guy was quite pleasant when I talked to them.

[jayvee]

Originally Posted by rachaelseven

So what if the chassis actually was energized to 12V just for a nanosecond? What if the water in the fuse box, where there is obviously plenty of 12V including the jumper cable point, connected 12V to the frame... not for long, a millisecond or less. The heat instantly vaporizes the water, breaking the short. But in that instant, the ground reference is gone or there is the effect of a 12V noise spike on ground. Maybe?

Well, I guess anything's possible - those darn electrons move pretty fast! But if that were the case, I would think it would have thrown more than just one code (ground is gone - and how many sensors must depend on it, or would get "flagged" for being at 12V instead of ground?)

All good theories...but just like how many licks it takes to get to the center of a Tootsie Pop, "the world may never know"........

[wfolta]

Originally Posted by JasonPro

I've been through a touchless wash several times now without an issue. I think you're on to something suspecting the fuse box getting wet.

I routinely use a touchless wash and have had only one problem: the last time the outdoor temperature sensor got stuck at 68 degrees (water temperature?) and didn't start rising back to actual ambient temperature until about 15 minutes later (including about 10 minutes at interstate speeds). After I got home (about 20 minutes), it had finally risen to approximately the proper temperature, and it was seemingly back to normal after that.

[sciguy125]

Originally Posted by rachaelseven

But in that instant, the ground reference is gone or there is the effect of a 12V noise spike on ground. Maybe?

Coincidentally, I was asked to look into ISO7637 at work a few days ago. It's the spec that covers voltage spikes on the 12V system in cars (or 24V for commercial vehicles). Cars are apparently very nasty places for electronics. All of the possible spikes are supposed to be from the various motors starting and stopping under various conditions (fans, alternator, etc).

One of the nastiest specs in there is that the electronics are supposed to tolerate a train of 2ms -100V spikes (yes negative with two zeros). Not that I recommend shorting the traction battery to the 12V system.

[Jim Calvert]

Originally Posted by rachaelseven

Today my partner took the 2010 IV through the car wash for the first time - automatic car wash where ......

I hand washed my 2010 Prius yesterday, and several times the car would beep whenever I ran my wet sponge over the driver side door knob. No harm done though, and everything was normal after I finished washing it.

[Bobsprius]

Jim,

Same thing happened to me when washing mine. I didn't have the FOB in my pocket but close enough to the car to note it's proximity.

Once I placed it farther away, no more beeping or locking or unlocking happened. A learning curve.

Thanks for your post as well...

[Mike Dimmick]

Originally Posted by jayvee

Well, I guess anything's possible - those darn electrons move pretty fast! But if that were the case, I would think it would have thrown more than just one code (ground is gone - and how many sensors must depend on it, or would get "flagged" for being at 12V instead of ground?)

The thing you have to realise about voltages is that they are all relative. There is no such thing as 'ground', only a reference point to which other voltages are measured. The other term for voltage is potential difference. By convention, the vehicle's chassis is considered 'ground'. Because the aux battery's negative terminal is connected to the chassis, the potential of the connections to the positive terminal are said to be at 12 volts.

The high-voltage battery's positive and negative terminals are completely disconnected from the rest of the car, the return path being a second conductor. The negative point therefore could give any reading at all compared to the chassis if you read it with a voltmeter.

'Ground' is really a term from transmission-line systems such as power distribution, where the Earth itself (i.e. the planet) is used as the return path.

Poor connections to 'ground' on one sensor, compared to the ECU that measures the value, can cause sensor values to be wildly out of range, because the two ground points have a potential difference between them (connecting a meter across the two points would show some voltage difference). Some of the car's sensors (e.g. coolant temperature sensor) are connected at two points, to provide a good reference ground, rather than being connected to the chassis. Some ECUs have multiple ground points and therefore can even show incorrect voltages within the ECU itself. An ECU fault should be diagnosed first by checking all relevant ground points, in my view.

So, if there was a short between the battery positive terminal and the chassis, the ECUs would see that as a reduced voltage on the power connections - likely they'd momentarily switch off.

[patanci]

Went through an auto carwash today after filling the tank but forgot to replace the gas tank cap. This is a high pressure water jet wtih no brush type of car wash. I wonder how bad it affected the car. I have the gen III prius. Appreciate any feedback.

[patsparks]

Originally Posted by patanci

Went through an auto carwash today after filling the tank but forgot to replace the gas tank cap. This is a high pressure water jet wtih no brush type of car wash. I wonder how bad it affected the car. I have the gen III prius. Appreciate any feedback.

Oh no!
Would be best to have the tank drained and then refill. I wouldn't drive the car until the water was removed. That's my opinion.

[patanci]

Originally Posted by patsparks

Oh no!
Would be best to have the tank drained and then refill. I wouldn't drive the car until the water was removed. That's my opinion.

Thanks, I will do that first thing Monday. I should be able to drive for few miles to the dealership since it's got full tank right now.