Is OBD P0401 caused by P0325?

[sifan]

My 1995 Toyota Tercel with over 300K miles first developed P0401 and failed the Maryland emission test this summer. I have to fix it or spend at least $400 to get a two-year wavier by November this year. Now P0325 comes up, too. I wonder if I replace the knock sensor to get rid of P0325, will this also fix P0401 automatically? The car had P0401 two years (or 30k miles) ago, and the mechanic cleaned the EGR tube to clear it. Now the same code comes back. I am on a tight budget and need this car to look for a job. Thanks.

 

[Jim 5]

Here's a link that might be helpful.

http://www.toyotanation.com/forum/archive/index.php/t-55168.html

 

[sifan]

Since my car does not stumble during deceleration , I think the EGR is still ok according to above link. I will try to replace the VSV and see if this will clear P0401. Thanks.

 

[Jim 5]

VSV seems to be a very common one on these Toyotas and the difficulty seems to be the intermittent nature. I'd try a junkyard one if you can get one.

 

[mechtech2]

Sounds like two separate problems.
They MAY be related if the EGR is blocked and makes the car 'ping' or 'knock'.
Then the KS comes into play.
Get the EGR right, first. Then clear the codes. Drive it so see what code if any pops up.
Your KS may have a bad wire, connector, or itself be faulty.

 

[sifan]

There are two kinds of VSV: one for the pressure sensor, and the other for exhaust. Is the one in question for pressure sensor? I will work on removing P0401 first. Thanks.

 

[sifan]

I just replaced the VSV for the pressure sensor and cleared the codes. Now the engine seems to regain power without stumbling. I will drive a while to see if the codes return. Thanks. I

 

[Jim 5]

Originally Posted By: sifan
I just replaced the VSV for the pressure sensor and cleared the codes. Now the engine seems to regain power without stumbling. I will drive a while to see if the codes return. Thanks. I


No problem. Hope this solves it for you. I'll bet it does, as it seems to be a very common problem on toyotas. And common things are common!