2000 Camry P0401 code

[jlaley]

I've read everything on this I could find here. Light has been on for awhile now. Time for inspection so I have to fix it. Here's what I have done so far. Tested the EGR by applying vacuum to it while running. Dies immediately. Starts right back up so it's not sticking. All the other posts lead me to believe it's the vsv so I order one and replace it. Light came back on in 7 miles. I checked vacuum at the throttle body and at about 2500 rpm's it has 20-24". Check at same rpm at the "Q" port on the modulator and it flutters some but basically the same readings. I removed the EGR to check for carbon even though it checked fine. None there. Figured it had to be the modulator so I bought that today. Installed and took the car out on the x-way at 65, no light. Girlfriend (her car) took it home and light came on 2 miles from my house. This is going to drive me nuts. Please help me figure this out. Thanks in advance. Jim

[Nervous]

Did you test the exhaust gas temperature sensor (the one screwed into EGR valve)? It can be tested by ohmmeter, FSM describes how (camrystuff.com).

And - to TN!

[jlaley]

Thanks for the welcome. I joined a long time ago but don't get here hardly ever. I don't have a exhaust gas temperature sensor on the EGR. Please elaborate.

[Nervous]

You didn't specify the engine, btw. 1MZ for sure has the EGT sensor, so I am assuming you have 4cyl 5SFE?

[jlaley]

yes, sorry, it is the 4 cyl. It has 130k on it if that matters.

[jlaley]

Can anyone please give me some suggestions?

[TOYOPARTSMAN]

I can tell you about 90% of the time if you replace the EGR valve, the VSV, and the Modulator it will solve your problem. However, if you did, or feel confident that these 3 items are all okay, the next thing to check would be the MAP sensor. That is what came up when I ran the P0401 code through my data base. My schematic is very vague, but it looks like its towards the back of the engine and has an 89420-06040 part number on it.

We don't sell a whole lot of them, in fact it has been awhile, so before you rush out and get one ($333.58 MSRP), I'd make darn sure that is your problem.



I hope this helps and good luck. If you need anything else, don't hesitate to contact me.

[matted2thefloor]

Not to sound stupid, but did you get the 2 vacuum lines put back in the correct locations on the VSV and is the connector seated properly? Every one of the VSVs that I have replaced for a 401 code after verifying that the EGR is good (the same way you checked it) has not returned with a light on again.

BTW...I'm a Toyota Tech...

[fenixus]

as per the MAP sensor replacement. hold it off as last one, it's the least suspected.

BTW, there is FSM with testing methodology (voltmeter and vacuum pump required) for MAP. though I have to warn you that Toyota took a very hard way to do this - back probing the terminals at ECM with connectors plugged in. you would need special back probe pins for that.

I found an easier way to do the same test at the MAP electrical connector and when using a couple wires with alligator clips on them. no need to do this at the ECM which is located behind the glove box.

to test MAP check out SFI FSM, page 53:
http://www.camrystuff.com/manuals/Gen4/SFI.pdf

and then this thread for a shortcut (post#335 & 336):
http://www.toyotanation.com/forum/sh...23#post3214023

most likely MAP is good, it almost always is, because when it's bad the engine would be running like crap and even stalling at idle or had zero performance. MAP is a crucial sensor.

check all the vacuum hoses if they are not clogged (blow air through them) and check if they hold vacuum when connecting one end to the vacuum pump and plugging the other one securely.

If you decide to replace those hoses, let me know, don't use the SAE hoses from local parts stores, they will NOT be a tight fit. you will need metric hoses - I know that 3mm ID / 2mm wall silicone hose off ebay (Honk Kong, member ID zenaracing, cheap and sells short lengths too) for all EGR stuff is best bet.

but you SHOULD double-check if REALLY the VSV for EGR works good and most likely get the modulator replaced (it has filter in it). then do some testing on the EGR valve itself, it's all in the links I posted either per FSM I linked or per thread I posted. been there done that and ended up up replacing all three plus hoses to make it a complete EGR rebuilt and piece of mind for future. BTW, thanks to it I got dismissed the issue with intermittent poor acceleration on my 5s-fe and restored the MPG on car that was suffering from too much fuel consumption.

if you have obd2 scanner handy that can show you live output of oxygen/afr sensors and fuel trims then this might come in handy when testing.

good luck.

[jlaley]

Thanks guys, I'm going to get back into this thing tonight after work. I will check the things you say and let you know what I find. Jim

[TOYOPARTSMAN]

I agree with fenixus about the MAP sensor. They hardley ever need replacement. As I stated in my earlier post.

Good Luck to you.

[TOYOPARTSMAN]

matted2thefloor,
It is nice to see a Toyota Tech in here. As a Parts Guy, I can only give the probabilities of what parts are needed based on sales, experience,etc. But I do know that there are ins and outs, and things in the repair process that I never hear about, i.e. the check the plug connection,etc.

Anyway, I just wanted to note that.

Originally Posted by matted2thefloor

Not to sound stupid, but did you get the 2 vacuum lines put back in the correct locations on the VSV and is the connector seated properly? Every one of the VSVs that I have replaced for a 401 code after verifying that the EGR is good (the same way you checked it) has not returned with a light on again.

BTW...I'm a Toyota Tech...

[matted2thefloor]

I'm still learning these Toyotas...I come from a background in Land Rover and Saturn. So these are the first imports for me. I really like working on them compared to the domestic stuff.

What ever came of the repair to the OPs issue?