Oil overfill caused complete shutdown

Sorry, I wasn't clear enough I guess. I didn't mean that adding too much oil would cause MG1 to snap the crank shaft-- that's silly. What I meant is that there is a safety mechanism built into the HSD system to prevent MG1 from applying too much torque which could result in a broken crank shaft if there were some problem binding the ICE from turning over as it should. And since a crank shaft is a very rigid body, the system has no choice but to be a little over-protective if it detects that MG1 hasn't turned as much as it should have when attempting to start the ICE. I'm not a metallurgist, but I'd put money on the difference in twist across the length of a 4 cylinder crank shaft between fully functional under no load and failing catastrophically to be no more than a handful of degrees. When you're dealing with such a small margin, your safety system has to react to very small variations from normal.

I don't know if that was the cause of OP's failure to start or not, but I thought the video was pretty informative and I couldn't help but notice the parallels between the reported cause and what the technician in the video talks about. I thought if it's a common enough problem that they'd teach mechanics about it in a training series, it'd be useful for Prius owners to know about it too so they can take simple precautions to prevent unneeded or costly repairs from unscrupulous shops.

The short version is, as nutty as the explanation might've sounded when diagnosed, there really is a rational explanation for it.

 

I saw similar symptoms recently as well on a 2005 Prius. Customer had some "oil monkeys" change their oil rather than a knowledgable Prius shop. Oil was filled about 3/8"-1/2" inch ABOVE the full dot.

Car coded almost immediately on the drive home.
Codes were P0A0F/204, P3190, P3102, C1259, and C1310

If you tried to start car, it would go READY then ICE would "run" for about 5 seconds then engine would die and READY would go off.

Trying to clear the codes with Techstream they would come right back. Disconnecting 12V battery wouldn't help either.

Here's what I did;
Drained out some engine oil so level just under full dot.

Removed air filter/MAF box (10mm socket), unbolted throttle body from intake (use 12mm socket), (unhook electrical connectors and PVC hoses but not coolant lines). Move throttle body aside. Cleaned intake and throttle body with throttle body cleaner and blue shop paper towels.

Sprayed MAF cleaner all over the MAF sensor then let dry in the sun.

Replaced throttle body gasket 22271-21030 and torqued to 15 ft/pounds

Reinstalled airbox, checked wires/hoses and car started right up and continued to run normally....then cleared codes and now they stayed away.

Funny how the repair manual says the solution for P0A0F/204 is to replace the engine ECU....$$$$......glad to hear the Austin dealer knows there stuff...

 

Thanks for sharing your story. I had an almost identical experience....to include many so called experts telling me that 1/4 inch over maximum fill line on dip stick could not possibly have caused my 2007 Prius (at 160,000 miles) to go into shut down mode (while I was driving on the expressway one block from the place that just changed my oil). After receiving no help from the Quick Lube that did it, I had my car towed to the nearest Toyota dealer (Sport City Toyota) in the Dallas area. I rented a car to drive the two hours home and waited for two days. The Toyota dealer was terrible. Told me the oil was not over the line. I said okay, let's check it. I opened the hood, got out the dip stick and started taking pictures of it. Only then did they acknowlege that it was overfilled. Then they changed to "no way the shut down was caused by the oil change, but it does now mysteriously neednew throttle body for $1500. Yup. And Quick Lube never answered my calls or my registered letter. I paid the money and it has run fine ever since with one exception - I have to add about 1 quart of oil every 500 miles. Never had any trouble before this and have always loved my Prius. But the service departments are another story.

 

This post is possibly really helpful to me as we left our 2001 Prius at Sears today and when we tried to start it, the thing went crazy and shuttered to a halt. Sears is trying to tell me that it is a problem with the Hybrid mechanics an it's a coincidence that it happened after their oil change. Seriously, dude?

Anyhoo, I read your post and I called and told them what they needed to do to fix it. They called me back and said that it still won't run. Do you know if after your mechanic cleaned the manifold, etc. if the car had to be restarted a certain number of times (similar to the gas cap reset).

Thanks for the help!!!

 

Clean out the throttle body plate, disconnect 12V battery and try restarting again.

If there are error codes and they have an appropriate scanner they can try and scan/clear the codes.

 

Old post I know, but I hadn't noticed it previous so I'll reply anyway.

When properly measured (level surface, oil fully drained back etc), an overfill of 1/4" (6mm) on the dipstick shouldn't cause any major problems. It's not desirable, I don't like to have any overfill at all, but up to 1/4" is not really dangerous. When I used to have my oil changed at the dealer (for warranty) they would always hand it back to me 1/4" overfilled, absolutely every time!

What I suspect we're seeing in these cases is an overfill which is *more* than 1/4" and the excess oil is rapidly consumed - drawn into the throttle body. So that by the time the "autopsy" is done it's only 1/4" over, but it may have been significantly higher before a whole bunch of it ended up in the throttle body..

 

Engine oil overfill or under fill is a pet peeve with me. I wouldn't trust anyone other than myself. When we pay for dealer service, we expect it to be right. I've had numerous instances where the oil level was overfilled at the dealer. Over filling is serious and every vehicle owners manual states that. Excessive oil can cause engine damage, but most likely damage the catalytic or "cadillac" converter as call it. Rule of thumb, always check and double check your engine oil level after change, regardless who does the work. If it's not at the right level, have them make it right before you leave. Also, I always walk around my vehicle checking for damage that wasn't there when I took it in.

 

pleasure.

 

Well, in summary, if you've got a problem like this, check if the oil is overfille, and probably, check other components-intake manifold, throttle assembly, MAF, etc.

 

Argh, looks like I may be in this boat as well. Meineke overfilled my oil about a half-inch above the max fill line, or about 0.5L.

What I got is a P0420 code though (so maybe just a gunked up catalytic converter) after driving ~50 miles over several trips.

So far I have no (apparent) engine or starting issues, and mpg (43) doesn't seem too out of the ordinary (for an 05 prius with original HV battery). Would it still be worth going through the cleaning steps 3prongpaul mentioned in #22 above?

More details at my post here:
P0420 code after replacing catalytic converter, slightly overfilled oil | PriusChat

 

You're Wonder Woman. You did a fantastic job. I think we live in a 3rd world country. Nobody knows how to do their own job and you have to come along and straighten them out. My hat is off. Bravo.

 

You did all the right things. I never could have done all that. Hired a flatbed? No. Quite amazing.

 

You're replying to a twelve year-old post and to someone who has not been on the forum for almost just as long.

 

But as long as we're doing that, I'll pick on 3prong for writing:

There's a little more than that in the repair manual.

P0A0F is one of those codes in the car where one ECU sets a code because of a problem detected by some other ECU that has more specific codes. It's like the P3000 code the HV control ECU sets when the battery ECU is giving specific codes about the battery.

In this case, it's the HV control ECU (kind of the orchestra conductor for the car) saying "I cued the ECM to start the engine, and it didn't happen, go ask him why." It has a few INF codes reflecting what sort of response it got from the ECM; 204 means the ECM said something about really low power output (the ECM's own code for that is P3190).

So, because P0A0F is one of those "some other trouble code has the real story" codes, its troubleshooting tree in the repair manual is really short. Step 1 is "read the other trouble codes. Then look those up in the DTC chart and fix them."

Only if that doesn't work do you end up at step 2, where you wonder if maybe the ECM is insane, and swap that.

Now all that said, there does seem to be one teeny editorial mistake, at least in the old 2006 edition I'm looking at. Step 1 tells you to go look for other DTCs and the expected "result" is that you get some. (Of course that's the expected result, 'cause P0A0F is a "there are other codes" code.)

Normally when they tell you to do something and what result to expect, they use OK to label what you do if the result was as expected, and NG for what you do if it wasn't.

But in this edition, they have the OK and NG swapped, so it ends up telling you that if you did see other perfectly cromulent DTCs, you should give up and replace the ECM, but if you didn't get any other DTCs, you should go fix those.

At least it's one of those mistakes you can pretty much tell is a mistake by reading it again. It's like somebody was thinking "oh, OK means no trouble codes" instead of "OK means you got the result we said to expect".

Somebody whose TIS subscription is currently paid up might check whether the OK and NG are still mixed up like that. If they are, TIS does show a contact form or email for reporting errata. I did that once and somebody got right back to me about it; they do pay attention to that.

 

I noticed the next sub-code's diagnostic steps, for the same procedure, use the words YES (there are other DTCs) and NO (there are no other DTCs) rather than NG and OK – and are correctly placed – which to me is more clear.

I have adopted that and corrected my copy of the RM.

 

Yeah, NG (presumably meaning Not Good or No Good, never seen it explained) in particular seem to be in common usage near-exclusively in Japanese Shop Manuals, or is it more generally Shop Manuals world-wide? It's usually in a critical troubleshooting procedure, seems cavalier to be using an obscure acronym is such a process.