Trans-fluid and scan code

[vectorg]

This year, I must get a smog-check when paying my car registration. How do I know if I should get some new transmission fluid at the smog place?

It's been 2 years since changing it, but the Camry went 7 years before ever getting a change at all.

My FE is good and I'm happy with the car.

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Also, my check-engine light is on!!! I plan to turn it off with my Scan-Gauge as I drive in to the smog place. What else should I do to make sure I pass the smog?

My code is P0446, which has lots of comments on the web about how difficult it is to correct. Any tips?

[Jay2TheRescue]

I recommend not going longer than 2 years without changing the fluid. Yeah, you can drive longer/farther but if you wait till you start having problems you've waited too long. ATF is far cheaper than a new transmission.

[bobc455]

I can't comment about the P0446 code because I don't know much about it.

However, if you do a drain & fill every 40k miles, you are way ahead of most people. Camrys have great longevity if you do the basic maintenance.

I know that many garages (including the one where I work) do a transmission 'flush' instead of a drain & fill. While I do like the thoroughness of this service, on my own cars I just do a drain & fill. It only changes about 1/2 the fluid, but in my mind that's enough to keep a fairly fresh additive package in there.

And it's usually fairly simple- loosen the bolts on the pan, let the fluid drain out, then install a new gasket and reassemble. I don't bother changing the filter, the transmission fluid seldom gets dirty (unless there are other issues). If you see really ugly fluid coming out, then you might worry about the filter (and about the other problems going on).

If you want to do a flush of your own (without the fancy machine), on some cars you can disconnect a cooler line and pump into a bucket, while simultaneously pouring new fluid down the dipstick tube. But to me, a drain & fill is just fine.

What have you learned about the P0446?

-BC

[theholycow]

I thought that you do the DIY flush by disconnecting the line, letting it suck in through one side of the line and letting it pump out the other side.

I have a P0446 sometimes on my truck. It seems to be related to the P0440 that has not been successfully diagnosed and also related to the only actual symptom I have, which is that you have to turn the key to "on" for a couple seconds before cranking (which indicates a fuel line pressure leak, probably in the fuel pressure regulator). I've been living with it for a few years and probably 50,000 miles. The symptom and the codes come and go on their own and the truck doesn't seem to actually suffer beyond the one symptom.

[jeep45238]

Evaporative Emission Control System Vent Control Circuit

This indicates that a part of the EVAP control system is no longer fuctioning correctly. The P0446 code is similar in nature to the P0441 code. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines
, carbon canister, purge valve, and other hoses. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

EVAP emission canister purge is contolled by a valve which allows engine vacuum to pull stored fuel vapors from fuel tank into the engine to be burned, rather than be vented to atmosphere. A vacuum switch is used to detect when flow exists. If the PCM commands purge and sees that the switch is closed (indicating no detected purge flow) P0446 is set.



When the vapor pressure rises to a specified point, the ECM opens the VSV for canister closed valve. Pressure will increase rapidly because of the air allowed into the system. No increase or an increase below specified rate of pressure increase indicates a restriction on the air inlet side. The ECM closes the VSV for pressure switching valve. This action blocks air entering the fuel tank side of system. The pressure rise on the fuel tank side is no longer as great. If there was no change in pressure, the ECM will conclude the VSV for pressure switching valve did not close.
http://www.obd-codes.com/p0446



Typically, I see EVAP codes caused over time by people topping off at the pump. Outside of that, it's generally a bad switch, vacuume line, or gas cap.

[Erdrick]

For what it is worth, my 2004 Corolla's owners manual specifically says to NEVER change the transmission fluid, unless you do a lot of towing or mainly drive dirt roads. IF you STILL want to go against what Toyota engineers advise you to do, and want to put in clean fluid, then please make sure that it is OEM Toyota-made! Anything else will likely grenade your trans.

Oh, and unlike an oil change, you can only get about 60% of your transmission fluid out at one time. The torque converter (and reverse maybe? can't remember where..) hold a lot of fluid, making it impossible to flush.

Moral of the story, skip the extras and just take the test.

[kamesama980]

if you clear the codes before going to the smog place you can still fail. if they plug their computer in and read that ____ self-test hasn't been run since the codes were reset you fail.

as much as I like toyota's engineering, nothing lasts forever. nothing remains leak free forever.

[vectorg]

Thanks guys. I'm going in next week, and I'll let you know what happens.

[vectorg]

Well, I turned off the code using my ScanGauge when pulling in to the smog place. Didn't pass. Went to the dealer, and they fixed it at a cost of around $280, but they didn't replace the charcoal thing. Today I went to get the car smogged, and on the way there, the light came back on with the same code P0446. I drove right past the smog place and to the dealer again, and they say I must now replace the charcoal canister. They're making me a deal and it will be another $275 or so, which they say is close to their cost and won't charge me any labor.

So far, I have 3 trips to the smog place and 3 trips to the dealer, and my light is still on and no smog certificate.

Are there any California laws that can help me out (lemon laws) if my car never does pass the smog tests?

California is bankrupt, but can I apply for assistance with the cost of this kind of repair after-the-fact to get some reimbursement?

[hi tech hillbilly]

Originally Posted by vectorg

Well, I turned off the code using my ScanGauge when pulling in to the smog place. Didn't pass. Went to the dealer, and they fixed it at a cost of around $280, but they didn't replace the charcoal thing. Today I went to get the car smogged, and on the way there, the light came back on with the same code P0446. I drove right past the smog place and to the dealer again, and they say I must now replace the charcoal canister. They're making me a deal and it will be another $275 or so, which they say is close to their cost and won't charge me any labor.

So far, I have 3 trips to the smog place and 3 trips to the dealer, and my light is still on and no smog certificate.

Are there any California laws that can help me out (lemon laws) if my car never does pass the smog tests?

California is bankrupt, but can I apply for assistance with the cost of this kind of repair after-the-fact to get some reimbursement?

wait, wait... you paid the dealer $280 to fix it, then CEL pops back up and now theyre gonna charge you another $275 to get it fixed AGAIN? I would speak to the manager about that and raise a whole lot of cane, especially if its the same code and related to the evap system that you paid them $280 the first time to get fixed..