When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello everyone, I hope everyone is doing well and in good spirits amid this pandemic. Several months ago, I bought a 2006 lexus gs300 with 204,000 (currently has 206,400). I posted a thread earlier in June in regards to a valve cover gasket change and spark plug replacement. Everything turned out great and I haven't had any issues with my car until a couple of weeks ago. A couple of weeks ago I got p0390 code (exhaust camshaft sensor bank 2) driver side if I'm not mistaken but the car still feels good, so I visually checked that the connector was on good and cleared it my scanner. Well 174 miles later, now I'm getting a p0393 code (Camshaft Position Sensor "B" Circuit High Bank 2) but the car still idles and starts up just fine.
I removed the sensor from the driver side valve cover, cleaned it with electric cleaner both sensor and plug. The rubber that holds the pins do look a little swollen but other than that, everything looks fine. I put everything back together and cleared the code and when I started the car, the check engine light came on with code p0393. The idle is fine and smooth but I haven't driven the car.....from my experience, these sensors rarely go bad as its a simple design which makes me think about the connector or wiring harness...any ideas? Suggestions? I'll take prayers and well wishes as well......
The spark plugs that you used, were they purchased from a reputable seller and not fake $22 a set densos that are scattered all over ebay and amazon. Has the car ever had any issues with carbon buildup? When you stop at a stop light does the engine want to die down? Have you checked oil level to make sure you are not burning oil? Is there soot on the rear bumper near the tail pipes?
Im thinking it maybe carbon buildup with the mileage on the car, and the sporadic engine codes. Im thinking the intake valves are carbon gunk up and are slowing the movement of the valves, causing the camshaft to read funny. No worries, what you can do is remove the intake manifold, and with long stiff plastic brushes and a good chemical cleaner scrub each intake valve. The job shouldnt take too much time, and the cars performance/fuel will perform a whole lot better.
The spark plugs i used were from Advance Auto so they should be legit. I took a picture of the engine without its valve covers, although it doesn't have anything to do with the intake valves, it looks like it maintained and has service records all from lexus BUT the tailpipes are dirty now that you bring it up.. i would just have to remove the air intake assembly and the intake manifold ( both pieces) and that would give access to the valves? Not bad for 200,000 miles.
Looks pretty clean for 200k its probably highway driven. But ya remove the plastic intake and I believe the aluminum intake below it and that should give you access to reach the intake valves with long stiff brushes.
Does look good for that many K's... Nice. The area of the valves you would want to clean I would imagine are at the bottom of the head that you are looking at in your photo there, accessed at the bottom surface between head and block (that set of springs you see are the valve springs around your valve stems & PS. Sorry if you knew that but covering it all, not trying to teach you how to suck eggs LOL). I am not sure if there is a way to clean those properly without taking the head off though.
Quite often cam angle sensor faults can be electronic so I would hit that first (aligning with your initial thoughts), there are 3 types most commonly (hall effect, optical, and reluctor), I am not sure what they are on these but knowing Toyota/Lexus they will be a reluctor type and confirmed by the harness to the sensor being a 2 wire. Reluctor sensors do get gammy after a while, especially when hot (maybe when it faults it's usually a hot day?). Very cheap typically, so don't be too concerned there. If it is reluctor, then is either that pick up, or the toothed disc it's reading, and I very very much doubt it's that disc!
Yep - Ensure continuity of those wires are good, or if the ECU has been in and out a couple of times the wires at that end (will be same colour) could also be a possible wiring thought after being manhandled a few times. Likely it's reluctor (need confirmation) and likely it's that pick up IMO. Idle will possibly be OK because either the ECU is registering the error but it's not a great enough error to give you any issues or you can't hear a light mis-fire... OR; because I think they have a pick up for each bank to work VVT, but only one is used/shared for the ECU ignition timing meaning the problem may not show itself until VVT is meant to be active (CAS utilisation statements also need a a confirmation as not sure with these).
If you have an oscilloscope, you can check the output voltage of the reluctor by testing it at the ECU or sensor end if it does use reluctor, and from memory I think this should be up around 1.7V-2V ish, any lower and I would look deeper in to this being a possibility. Shielding of signal wires could also be an issue, these CAS wires should be shielded and typically at one end only, if they recieve stray electrical noise the ECU could be thinking it's received a firing event out of order throwing the code. Just some thoughts.
GS460, it does use a reluctor wheel which is on the camshaft. i have a friend that works at autozone, i was thinking of getting the sensor and if that does the trick either keep it or return it and buy a denso from rockauto. Moreover, since this car is direct injection, it's only natural for the intake valves to get gunked up so I do plan on cleaning those valves but just want to make sure that will disable the check engine light as my OCD is getting to me with that light.
So i removed the sensor and switched it with the passanger side sensor and no change on the code, so one can say the sensor is fine. I inspected the connector and pushed in the three pins and I don't have the check engine light anymore. I'm going to drive the vehicle and see how long it lasts. Which brings me to another question, how can I re pin the connector? Or should I go to the junkyard buy another connector and splice new wires?
If the pins just got pushed out, what you can do is with a pick, pry out the water proof rubber seal just a bit. Just the wire back in the slot until it clicks and locks into place. Then push back in the rubber seal
So i removed the sensor and switched it with the passanger side sensor and no change on the code, so one can say the sensor is fine. I inspected the connector and pushed in the three pins and I don't have the check engine light anymore. I'm going to drive the vehicle and see how long it lasts. Which brings me to another question, how can I re pin the connector? Or should I go to the junkyard buy another connector and splice new wires?
What ibidu1 said is good advice, i'd go with that, splicing is easy, if you want new they are not cheap for a connector, and assume you've given the pins a wee check over for oxidisation/cleaned 'em up a lil for sake of continuity. Here's hoping that bit of a re seating did the job 👍
09-08-20, 09:00 PM
P0393 code
