Good evening fellas!

Have a weird one here and cannot figure out how to resolve it. 2010 Rx 350 FWD been lighting up the "check engine/traction control" cluster indicator lights every now and then. Car rides perfect before and after the light come on. To "momentarily" resolve it I remove the gas cap and retighten. 40 or so miles lights goes off and then my take a few days for it to happen again.

Thinking it was a bad gas cap, I purchased a new Lexus branded cap matching the vehicle's VIN# but that has not fixed it and the cycle continues.

Tonight it happened again, and for ****s and giggles I pulled my OBD2 reader and the vehicle is reporting a current DTC of P0335 (corrected) which is for "Crankshaft Position Sensor A Circuit". I am puzzled. What the heck does that code has to do with me messing with the gas cap?

Any clues?

Thanks,

Edwin

 

Probably has nothing to do with your gas cap.
Intermittent codes resolve themselves after so many cycles if they don’t repeat, would of turned off on its own, just a coincidence with your gas cap tightening.
also, double check your code, I thought P0335 was Crankshaft position sensor, P0355 should be a coil error code?

 

Check your battery. How old is the battery?
A failing battery with low voltage will trigger many random codes and warning lights as they are very sensitive to low voltage.
I cannot count how many times folks have posted about a similar situation and a new battery resolved the problem.
You can get it checked for free at most chain auto parts stores.

 

^^ What he said.

 

Replaced the battery for a new one and erased the code. Drove to the coast this weekend and on the way back the code came right back.

No change whatsoever in the way the vehicle drives and behaves, just the "engine and track light". This is so odd.

Thank you for the commentary so far fellas.

 

Please re-read the codes and confirm. Also check Pending codes. If too many codes, clear them and reread on the first onset of CEL.

Do not try random stuff based on instincts. You will get conflicting messages if one of the un-needed change brings about yet another problem. You will be wasting money too.

For CEL based detection, Clutcheless gave the perfect start point ... make sure your 12v is good.

Salim

 

Apologies as I typed the wrong code. I have gone and corrected it. It is a P0335 for the Crankshaft Position Sensor.

I just pulled the freeze data and PCM voltage was captured at 13.13V which seems very low. I went ahead and ran an alternator charging test and I am getting a VPWR of 13.36V. Seems as if it is charging to around 13.3-13.6V

I wonder if the P0335 is being caused by a low charging/failing alternator.

 

That is certainly a possibility -- your voltage is indeed low.

 

The voltage seems to be in the right range 12v min. The problem maybe in the spikes of either high and mostlikley low [or dead phases]. The alternator produces multiphase ac voltage which the rectifiers pass the right phase to the system. These diodes are in the alternator. These overlapping waveforms produce the smoother DC signal. If a phase is missing you do not the right averaged peak. [This is what I speculate is happening].

This may not be happening to you, but in my first gen, when my 12v battery died, it was due to a shorted cell. Unknown to me, but this short stressed out couple of diodes in the alternator. Soon after I replaced the battery my ABS light kicked in and I spent months chasing the problem. I finally decided to get the alternator bench tested and sure enough it failed. I just swapped the diode pack and put in new brushes and the problem was rectified [ha ha] and no more ABS.

Once again have the alternator bench tested, before you take the next step.

Salim

 

did a charging test and came back with 13.45V loaded and 13.47V unloaded with ripple being 31mV.

Engine/Trac light are now off once again. This is so weird. Can a Crankshaft Sensor go intermittently go bad and trigger warnings without any noticeable change to the the way the vehicle drives?

 

Almost like when I am told about my blood pressure readings and I have to ask "is it good or bad". specially the ripple.

It could be my ignorance, but I was expecting 14.1v. I will let others who know better comment on this.

The next set of question are:
What is the current milage?
Any chance of sensor wire loose/chewed through.
What are the pending codes? Hopefully they are the same.

As a last resort, you can change the sensor but make sure you get an OEM from reputable shop.

Salim

 

back from the dead. Same symptoms years and many many miles later.

New OEM alternator and new OEM crankshaft sensor. No other pending codes and the same P0335 keeps randomly showing and clearing itself off.

HELP! No one I have taking the vehicle to has been able to determine the cause.

 

I assume no rodent issue or wiring damage is there? Have some one trace the wires and look for tell tale green oxidation traces on contact or wire.

There are times when the vehicle has to be taken to a shop and this might be one. Also keep in mind the shop may not be able to diagnose... intermittent problems are very hard to diagnose.

Salim

 

You may want to consider attaching a code reader (like scan gauge) while you drive, that way you can check pending codes at stop lights, so you can catch it in real time.

I usually buy cars with over 90k on them cuz I enjoy wrenching, so I always have a code reader hooked up, and I like to monitor coolant temp, battery charging voltage, and other stuff the ecu monitors.

over the years I've caught a variety of issues like when the alternator took a dump on my 996. Or when a coilpack was on the fritz on my 3rd gen miata and also on my beater rx330.