bryarblue

Hello All :

Problem Background
I took my Lexus ES 350 V6 (with approximately 100K miles) into the shop in late January with an oil leak and misfire on ignition coil #3. The engine had to be removed to repair the oil leak and of course with the engine removed the #3 coil replacement was easy.

I picked the car up and drove it a couple of miles and before I got home, the Check Engine/VSC/Traction Control indicators appeared. With the errors, the car still runs very smoothly without any other indication of the problem. I drove the car straight back to the shop. My mechanic hooked his diagnostic equipment up to it and announced a Crankshaft Alignment error. So I left the car with him.

Current Situation
My mechanic replaced the crankshaft position sensor and it did NOT resolve the problem. Because I have multiple cars, I told him that he could work on it as he finds time. Because the sensor replacement did not resolve the issue, he believes the issue is somewhere in the wiring and has spent many sessions with logic diagrams, and test equipment but alas, has not been able to resolve the issue. Today he said he is running out of ideas but said he would continue looking at it. He said replacing the cars computer was the last ditch option because he said computer replacement does not have a very high success rate in fixing electrical problems (in his experience).

Question. Could the crankshaft position sensor be correct and there really is a misalignment error? Does the crankshaft position sensor work with a cam position sensor and if they are out of sync, it will throw this error? If so does that mean the timing belt may be worn out and needs replaced?

I am pretty frustrated at this point. I've used this mechanic for at least 20 years to repair my family cars and he has always been extremely competent and trustworthy. I believe he really is doing the best he can on the issue.

Has anyone else seen or heard of this problem? If so, what was the resolution. If not, do you have any ideas ? Perhaps I can relay them to my mechanic and expedite getting my car back !!!

Thanks in advance!

Roger

nevernu

I recently had a persistent code P0500/MIL/VSC problem that required a lot of troubleshooting and it turned out to be corroded wires in the wiring harness underneath the engine fuse block. I dont know where your particular harness runs but fyi

bryarblue

Thanks for the reply. Was yours an ES 350 also? If so, what year?

nevernu

07 es350 w 160k km
check out post 10 onward

Hayk

iTrader: (1)

If the engine had to be removed for an oil leak that sounds like they fixed the front timing cover - very common failure for these engines. That's a deep surgery and it's possible something wasn't installed properly or may have been damaged during reassembly. Do you know if they lowered the engine with its subframe out of the bottom or if they used an engine hoist to lift it out of the top?

These engines are timing chain driven, which are not known for stretching at 100k miles. The chain should be good for the life of the engine.

Mechanics usually have a tool for measuring signals from various sensors on the car called an oscilloscope. In theory he could connect to the Crankshaft Position Sensor with an oscilloscope and see if the waveform and values coming out of the sensor are normal. That would verify if there is an alignment issue or a signal problem with the computer. Computer problems are extremely rare so I agree with your mechanic. It's more likely there is something going on with that tone ring inside the timing cover.

Here is some reference photos from the YouTube video below of where the Crankshaft Position Sensor is situated. If you look closely you'll see the tone ring that spins next to it to give the computer its readings. The alignment issue would be between the sensor and that tone ring.






I also attached the Toyota Service Manual procedure that shows the Crankshaft Position Sensor



You can watch the repair process here to become more familiar with it.

ESh

If they removed the front cover probably they bent or damaged the big pulley or the plate that goes under the sensor.

bryarblue

Thank you. That was an interesting post. I'll mention this to my mechanic.

bryarblue

Hello Hayk.

That was some very interesting stuff. Thank you so much for taking the time to post it. I am now more educated on this engine and what my mechanic had to go through to fix the leak and subsequently replace the position sensor. Yes, my mechanic did reference "dropping" the engine to make the repairs. He also mentioned watching an oscilloscope while trying to catch the error as soon as it occurred. Finally he referenced using Toyota logic diagrams (pretty sure he said Toyota and not Lexus... don't know why).

As another member posted in this thread, could something have become damaged during the original oil leak repair procedure? Recall I mentioned that I picked the car up after that repair and brought it back immediately with the new crankshaft position error.

Oddly, and I am not sure if this gives any additional clue, but I think my mechanic mentioned that the error seems to only come in when the car is sitting still and idling and not when it is in motion. In fact, after I picked the car up, the error only popped up when I was sitting in a 7-11 parking lot with the engine running at idle.

Regards,
Roger

Hayk

iTrader: (1)

At this point it’s gonna be up to a mechanic to find the source of the problem but it’s hard to argue that the engine repair is not related to the failure. If they removed the engine and/or did the front timing cover, they gotta own this repair.

bryarblue

Thanks Hayk.