SCuster

What did the fix cost you? When you wrote "ticking" you hut the nail on the head. It only ticks when cold. Once the engine and exhaust warm the ticking stops. Unfortunately the codes are reading insufficient Bank1 and Bank 2 so I'm not sure how to determine which side is the culprit. I cant imagine both are bad.

rogerboyd

You don't need to remove battery to replace that bulb - it's easily accessible from under the car next time you need to replace it.

rogerboyd

You don't need to remove battery to replace that bulb - it's easily accessible from under the car next time you need to replace it.

Fourthoren

I'm posting this as a way of saying thank you to the forum. Yesterday the vsc off, trac and check engine lights came on. I read the posts and because I'm an engineer, I started with the simple things first. I recalled that the gas cap was not going on as easily as it was prior to our Xmas road trip. When I checked the cap it was not seating and compressing the o ring. Instead you could tighten it, it would click but the cap was not tight and you could easily loosen it. So, I went to the Toyota dealer, got the Lexus GX470 cap for $23 and placed it on the filler and it was clear that was the problem because the new cap seated and sealed nice and tight. Since the light did not go off, I again took the easy path and disconnected the negative terminal on the battery and let it sit for 30 minutes. Reconnected it, started the car and problem fixed! The lesson learned is to try the simple things first and don't overthink problem solving :-)

RoseHill1

1/3/14 afternoon, my wife drove our new used 2006 GX470 home from work, and the VSC TRAC, VSC Off, Slip Indicator, and CHECK ENG Light all came on at the same time. The manual indicates that the gas cap, or EVAP system leak could be the problem with the Ck Eng light, but the other lamps indicate failure of the traction system. I checked the codes at our local Auto Zone, and P0456 was set, which is the the fuel cap, evap can, vac line leakage, or pump failure. Would anyone have any ideas other than a dealer visit?
Thanke for your help.

RCsGX

Those lights will come on as well with the check engine light if it's a gas cap. Try the cheapest solution first, which is a gap cap replacement.

chrisv78

Also check the vacuum lines, especially behind the filter and at the evap canister. On my SC430, someone messed with the filter box and knocked the evap canister vacuum line loose. No cost fix thanks to the Autozone code reader.

RoseHill1

I checked the gas cap first and it's not locking down securely, so it's time for a new one. Disconnected the battery to clear the codes and haven't seen them again after several days driving. Will order a replacement gas cap when I find the best pricing.

Thanks to all of you for all the support.

lesz

We have had 4 or 5 straight days of below 0 temperatures, including 2 days where the low temperature was between -20 and -25. After not having driven the GX for 5 days during the extreme cold, I started it up this morning. It did start, but it had to crank for a few seconds before the engine started. After it started, the check engine, traction control, and skid control lights came on and stayed on. According to the Lexus service adviser with whom I spoke, if the engine takes a bit of time before turning over, the computer's sensors detect unburned fuel in the engine, and, when that happens, that triggers the check engine light. He also said that, when the check engine light comes on, the traction control and skid control systems are automatically disabled (I'm not sure why that is the case).

He said that, while he can't guarantee that there isn't some other issue, once the codes are cleared, it is likely that the warning lights will all turn off. He said that starting the vehicle and driving it normally while giving the engine a good chance to warm up and doing so several times is likely to clear the codes, or, alternatively, the codes could be manually cleared. Further, he said that they often see instances of this array of warning lights coming on under two circumstances. The first is, like my situation, when there is extreme cold, and the engine takes a few seconds to turn over. The other is when people start their vehicles in cold weather, pull them out of the garage, and shut them down after being on for only a few seconds and before fuel in the engine has a chance to be burned.

Anasazi

Wife's '04 GX470 had the same lights come on. Bought a new gas cap from Toyota dealer for $21 - identical cap was $36 at Lexus dealer BTW. Lights still on after new gas cap. DC'd battery for 30 mins, reconnected, problem solved. S'pose I shoulda tried Dc'g battery by itself first

TighNaLoch

Same thing happened to me. 2009. New Gas Cap $47 fixed issue right away.

lesz

You are going to have to wait a while before you know for sure whether your problem has been solved. When you disconnected the battery, you cleared the codes. If there is still a problem with the emissions control system once the codes have been cleared, the vehicle will have to fail the test 3 consecutive times before the warning lights come back on, and the test of the emissions control system will only be performed at some predetermined time interval. Thus, that third consecutive failure might not happen for several weeks. If the lights don't come back on within, say, a month, you are probably good.

RCsGX

x2 on what lesz.

If it was due to the gas cap the light would've gone off within a certain amount of miles.

chiph9

I'm wondering if I should just go ahead and replace the cap as a preventative measure.
It is ten years old, after all.

Chip H.

TighNaLoch

You can tell easily if the Gas Cap is the issue. When you turn it closed and it clicks once you know it's locked.... but if when you turn it to open it, it opens very easily to the left with no pressure the seal is baked out and not working, which is what caused my error codes.