2012 Prius refused to Start. Error Code P0335 – Crankshaft Position Sensor A Circuit Malfunction

The players in that game are the crankshaft position sensor, the wiring and connections from there to the ECM, and the ECM itself.

If you're sure the sensor and the wiring and connections have no problems, the ECM is what's left.

However ... it is not at all common for ECUs to fail. That could be a reason to review carefully what steps you used to become convinced the wiring and connections and the replaced sensor are definitely good, before condemning the ECM.

Are you able to crank the engine over by using a power tool on the crank bolt, for example? If you attach a scope at the sensor wires where they meet the ECM, do you see the expected waveform?

 

You reported a P0335 code, which is a certain indication that either (1) the crankshaft sensor signal isn't properly reaching the ECM, or (2) a proper signal is reaching the ECM but the ECM thinks it is not proper (which would make the ECM at fault).

An oscilloscope at the ECM connector where the crankshaft sensor wires arrive would be about the most definitive way to distinguish (1) from (2). If the signal is poor, you can concentrate on what is wrong with the sensor or wiring to make it poor, or if the signal is good, you can conclude the ECM is at fault.

 

I would suggest unplugging the ECM connector that has the wires for the cam and crank sensors. Then carefully back probe each circuit (from the wire side, not the terminal side that goes towards the ECM) and test resistance for both sensors (see the service manual for specs)- and check for any resistance to ground (should be infinite resistance).

If that checks out ok then you may need to have someone with a 2 channel scope test both sensors to see if they can put out correct signals and that the signals are in the proper relation to each other (aka- correct cam timing or "sync").

Sometimes a bad sensor can fool the ECM into coding the "good" sensor- as can a cam that's out of time. IF you can verify that both signals are correct and sync is correct THEN I might consider the possibilty of a bad ECM (after load testing all ECM power and ground circuits).

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I recommend that you contact an electrician. You may have a malfunctioning sensor.

 

What are the trouble codes that now appear, after your most recent changes? That's the first important information to get.

What starts the engine is the motor-generator MG1, located inside the transmission. It is difficult to access. More to the point, there might not be much reason to suspect it, at least not before knowing the most current trouble codes.

 

Have you made any effort to rotate the crankshaft (by hand, with an assistant, or with a power tool) while observing the crankshaft sensor signal at the ECM connector with an oscilloscope?

I see that you have posted this:

... by which I suppose you mean that you tested the sensor with an ohmmeter. So it was in the specified resistance range, which does make a sensor issue look less probable.

On the other hand, you now have two different ECMs agreeing that there is an issue with the sensor signal.

That could be a good reason to go further and view the sensor signal on a scope while the crank turns, as mr_guy_mann suggested in #5.

"whatever remains, however improbable, must be the truth."

 

Hi I have this same problem let us know if u solve it

 

Have done zero point calibration.?

 

Hi have you gone through the troubleshooting steps for your code in the repair manual (more info) yet?

A lot of the time that will get you directly to the solution. If there's something about the issue that still stumps you even after that, the brain trust here can bat it around some.

 

Hi thanks for replying
Basically car has p0335 code and won't start. Tried new crank sensor checked wiring changed invertor. Checked hv battery it has 215v dc.
Now stripped out timming chain and reluctor ring has slight play when rotated on crank shaft.
Think I will replace new reluctor ring and if still won't start then change transmission any input guys.

 

U had any further luck progress
I have exact same problem.

 

so you reprogrammed your smartkeys too?

 

Hi I was wondering whether you were using the troubleshooting steps in the manual to kind of focus you on the things you can check that might lead most quickly to a solution.

It sounds like you're trying a lot of things and will probably get it sorted that way eventually. I'm just not sure I would have the patience or money to attack it that way.

 

just had one set that code, ended up being cam sensor Wth? Car just gets confused…

 

Ok I’ve just been thru this code with no start as well ….. have you verified if the engine is turning over at all when starting is initialized.
Because if you look in and see that that crankshaft is not turning at all …and have a po335 code which makes sense since the sensor isn’t providing any data….you have likely have a busted output shaft on the transmission. That’s what mine was POW
Snapped right off .

 

Thanks for ur inputs, I still have to remove engine to see what's happing with cvt shaft flywheel etc. Will keep u updated, worse case is a engine and transmission replacement.