Engine Rattle when Traction battery low

Mine is the same. It runs perfect aside this scary knock with the traction battery at 2 bars under very light acceleration. I wish someone has the affirmative answer on what the problem is. Mine has been doing it for about 30,000 miles. There was one guy who thought that he had fixed his problem by cleaning the intake manifold, but later said that did not fix it. I use premium fuel exclusively and add a bottle of Chevron complete fuel cleaner once a month. This helps tremendously, but does not cure the problem. Still getting good gas mileage.

 

Anybody go to the dealer to get a diagnosis?

 

Yes. They replaced EGR and EGR cooler line and spark plugs. No change. Never throws codes either. Never has.

 

The EGR circuit runs from the exhaust manifold through the EGR cooler, EGR valve, EGR pipe and the full length of the intake manifold. In a situation with substantial blockage throughout the entire circuit, cleaning 1 or 2 or 3 parts of the 4-part chain can leave you with the same blockage as far as EGR flow is concerned. This guy likely still had blocked cooler, valve and/or pipe.

So it sounds like your intake manifold has not had it's EGR circuit cleaned, which if so, may likely be why there is no change in symptoms. Experience with my 2010 is that the intake manifold is prone to the heaviest blockage of the entire EGR circuit. But I don't feel there is a definite pattern and GUESS that driving patterns and degree of oil burning keep this variable among turd gen Prii. The only way to rule out EGR blockage as the root of your issue is to clean, or at least put eyes on the entire circuit.

Of note, only a small percentage of turd gen owners who report EGR issues ever throw the related code (P0401).

 

What I can't understand is why this happens with a low SOC with the hv battery. Has anyone cleaned their throttle body and MAF sensor?

Maybe fuel injectors? Not getting enough fuel pressure at lower RPM

 

Perhaps the heavier percentage of ICE demand when low SOC accentuates detonation from lack of EGR flow?....

For clarification, I'm always guessing with regard to my EGR design fail theories. No basis in anything but my own thought process. A limited intellect thought process at that...

 

I can't understand that either. The only thing I can come up with would be the power that is being drawn from from the engine for the HV battery to be charged, in conjunction with the throttle being engaged causes it perhaps. Just a guess. I would just like to have it resolved. Sounds like it may be the EGR in some way based off what I am reading. Wish we could find an answer from someone who has managed to completely resolve this. The dealer was useless.

 

If premium fuel cures the problem then you have a [very common] case of carbon buildup in your engine increasing compression and operating temperatures. This buildup originates from two main sources: PCV and EGR. The solution is to clean the carbon from the engine. Depending on the severity this can include any or all of the following: the PCV and EGR systems and (where their flows converge) the intake manifold and combustion chambers. The Combustion chambers can be cleaned with piston soaks, fuel system cleaner, and top-tier gas.

The Installation and maintenance of a PCV catch can (like the one @danlatu expounds on) is very likely to eliminate future manifold fouling.

Thus we arrive at a common set of solutions that fix many common engine problems reported by PC members.

Pixel XL ?

 

I am going to replace the PVC first, then go from there. Willing to do everything you suggested if necessary. Planning on starting with the easiest first. Since they replaced EGR and cooler, I would suspect it is okay. EGR was replaced about 15,000 miles ago with no changes. I will have to locate the PCV and change it when I get home next week. I have a feeling it is going to be some occlusion within the intake manifold. Honestly, I didn't think the Prius has a PCV. Thanks for all of the advice. Keep it coming.

Pixel XL yes! Great device. Best I have had. Had Samsung S6, Note, and Droid products before. XL 2nd generation will be out sometime in October.

 

Yeah I'm enjoying the Pixel. It's had great battery life so far... Love the biometrics, camera

Pixel XL ?

 

Hi Tanderson82, I just like to share my experience that cleaning the EGR pipe fixed this problem for me (i have had the EGR valve replaced by dealer too), so this problem must be related to EGR. I drove about 500 miles now and it no longer vibrating like mad at low speed / low battery when the engine kicked on early. If you have already cleaned your pipe it could be your intake manifold / cooler that is blocked

it seems like the engine was starved of air and vibrated because of insufficient EGR flow.

 

What did you clean? Just the pipe that was replaced by the dealer?

 

I'm thinking idling engine is when something like EGR or PCV clogging is going to be most evident. The only time the warmed up engine idles is with low hybrid battery is all.

 

I cleaned the EGR pipe for the code P0401 (Insufficient EGR flow), I posted pictures of the pipe in my other thread. Previously the dealer replaced the EGR valve for the same code and it came back. The code is now gone after cleaning the pipe.

The intake manifold has a lot of carbon deposit in it too but I haven't had the chance to clean it, good chance the EGR cooler needed cleaning too like everyone said.

 

Did you ever figure this out?

 

Salam. etdiniz fix that problem. And your video unavailable to watch now.

 

have you solve this problem? Please share your further experience.

 

everybody.
Repaired tons of priuses, got one day this rattling issue only while charging hybrid battery.
Did deep diagnostic, a lot of live data, but wasn't able to pin point the issue.

So did next:
1. Engine replaced with damper. NO EFFECT. Put the old engine back.
2. Transmission replaced. No effect.
3. Replaced all engine and transmission wiring. It goes in one piece. !!!PROBLEM SOLVED!!!

I'm not responsible for any misdiagnostic, based on my experience. Just sharing my experience.

 

Did you perform a new deep diagnostic after replacing the electrical wiring?
Were there any changes in the diagnostic data?

 

I did diagnostic before wiring replacement:
1. Oscilloscope + Toyota oscilloscope diagrams
2. Techstream live data + Toyota service manual

Nothing out of specs before wiring replacement, no changes after.

Also previously had one rattling prius with bad injector.