in5anem0ti

Hello!

I am new to this forum and was hoping to get some advice on a problem I have been having with my 2007 ES 350. The problem started a few weeks ago when the CEL Light, VSC Indicator, & Slip Indicator appeared on my dash. I checked the Engine codes and they were: P0300, P0301, P0303, P0302. I took it to the Lexus dealer and they recommended me to replace one of the ignition coils, all spark plugs, the radiator cap, and add some more coolant. (cost $1000 cad) The day after the service, all the lights appeared again. I also noticed that the engine temperature needle was moving from the middle to the hot position and back to the middle every few seconds. This time they recommended me to replace the temperature gauge valve in the engine. (Cost $350 cad) One day after this service, all the lights have appeared again. I checked the engine codes and this time they were P0302 and P0301.

Does anyone have an idea about what the problem is and what can be done to fix it? Thank you.

Clutchless

Obviously your dealer is just guessing and does not know how to do proper diagnostics and is just robbing you blind. You may want to contact Lexus corporate, however...
I would consider taking it to either a different Lexus dealer, a Toyota dealer as the Camry has the exact same engine, or a good independent repair shop.
Did they see if you had any animal chewed up wires? That is becoming more common.
I am also surprised they did not replace all the coils, especially the hard to reach rear bank since they were there replacing the spark plugs. You may have still more bad coils I suspect as that is the most common cause. Which coil did they replace? Cylinder 1 or 2? I would next replace the other cylinders coil.


The P0302 code means that the cylinder 2 is misfiring or is randomly misfiring.
Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 2. This is the front bank passenger side cylinder.
P0301 TOYOTA - Cylinder 1 Misfire Detected. Same procedure as for 2. This is the passenger side rear cylinder.
http://www.tsienna.net/random_multip...cted-2227.html

Did they check that your battery was good? Low voltage from a failing battery can trigger a lot of warning lights and other issues. You can have one of the chain autoparts stores do a free battery check which they offer in hope of selling you a new battery which most will also install.

Wilson2000

Other posters have found that a low battery can trigger the CEL Light, VSC Indicator, & Slip Indicator lights. If it happens again, check your battery with a VOM and make sure you are over 12 volts with the engine off, and 12-14 volts with the engine running.

in5anem0ti

Just an update, the third time I went into the dealer they concluded that the problem was that the head gasket is leaking between cylinder 2 and 4 and so my car needs a new engine.

Any idea how this could have happened and if there are any alternative remedies I should try?

They quoted a used engine at $7000 cad.

ESh

OMG. There's no possible way that a car can throw those codes if the head gasket is leaking in the ignition chamber, and there's no way that can the head gasket leak in 2 banks.

I would top it up with coolant and I would swap the coils.

Wilson2000

I agree with much of this, but cylinder 2 and 4 are both on bank 2, so there could be a leak between these two cylinders. Try some Bar's Stop Leak in and see what happens. I'm curious why the dealer wants to replace the engine rather than replace the head gaskets. Is the work less expensive? Is this a high-mileage engine? Did the dealer check for combustion gas in the cooling system? If not, you can buy a kit on the internet and check it yourself. It is possible to have a combustion leak between two cylinders without gas showing up in the cooling system, and in that case, stop leak won't help. But, because you mentioned you were low on coolant, I assume the head gasket leak involves your water jacketing passageways.