My Camry Failed Inspextion. Code O0401

>

Remove the EGR valve and EGR tube from the vehicle, then remove the tube from the EGR valve, then clean.

How do you know that it is not likely that the tube needs to be cleaned?

Unfortunately, Autozone does not have an online repair guide for the 1997 Camry. They do have a guide for the 1996 and earlier Camrys, and the illustrations at least show you what the parts look like and where to look for them.

In some applications, the tube is part of the EGR valve and in others, the tube is a separate part that is attached to the EGR valve. I believe that the tube is a separate part from the EGR valve in the Camry. As Bruce suggested, after you remove the tube from the car, spray some carburetor cleaner into the tube and use a piece of solid #12 or #10 electrical wire or a coat hanger wire to dig out the carbon buildup.

Also part of the EGR system are a EGR exhaust gas temperature sensor and an EGR valve position sensor. Unplug the wires from the sensors and vacuum hoses from the EGR valve before removing the EGR valve from the engine.

Have you tested to see if the EGR valve is working yet?

I would not start replacing parts based on the price. I would check the parts and their function first, then replace the part that tests bad.

I did not test the EGR valve. How do I do that?

I posted this before, perhaps you missed it. Apply vacuum to the EGR valve to open the EGR valve while the engine is idling and see if the engine starts to run poorly or starts to die. If the engine starts to run poorly and starts to die, then the EGR valve is working properly and the valve and tube are not clogged. The next thing to check would be the EGR position sensor if the EGR tests OK.

Anticipating your next question, you can apply vacuum to the EGR valve with a Mighty-Vac tool or you can bypass the vacuum switching valve and EGR modulator and plug the vacuum line directly into the EGR valve.

If the engine runs pretty much the same when you apply vacuum, then the valve is not opening or the valve and/or tube are clogged.

The problem with driving today's modern vehicles is that they are pretty reliable, and so it is easy to lose track of parts prices. It seems like the only cheap parts on any car nowadays are fuses and light bulbs (other than headlamps).

Just picked up a '93 Escort that had been sitting in a friend's driveway for

5 or 6 months. It is going to need a new battery, a bunch of bulbs, and rear shock supports. The hood won't latch and the gear select lever takes a lot of effort to move, hopefully those are just adjustments and cleaning. It barely makes 30 MPH with the engine revving, I'll have to investigate a little further.

This is telling me that I have to take it to a mechanic. I do not know how to do this stuff.

Unfortunately, not all mechanics know how to do this stuff either. If you are in the U.S., take it to a Toyota dealer or shop with ASE certified technicians, or look at the instructions at autozone for the 1996 Camry (different, but close enough to get the idea of how to check).

I don't want to step on anyones toes here. If it's a 4cyl. get some "Seafoam" in the spraycan with a straw ( I like to tape the straw in place ) then disconnect the pvc hose , start the car up and spray into the hose. It will directly hit the egr valve and it'll clean what sludge off of the egr. there will be some smoke coming out the exhaust. Thats a good thing, it's cleaning it.

If the valve isn't working properly. I suggest a new one from Rockauto.com for $126. Take a look there's a picture , it'll give you a good idea of where the line that extends to it goes. In any case good luck.

>

How does the Seafoam go directly to the EGR valve from the PVC hose? Something sprayed into the PVC hose would normally have to pass through the throttle body, intake manifold, and combustion chamber before some gets drawn through the EGR tube and valve. The stuff must be pretty potent if it will clean out a blocked EGR system. Seafoam's web site mentions that it will clean EGR systems but doesn't explain how it works. I've read several posts from people who say that Seafoam works well, although I do not have direct experience with it.

Possibly worse. It has an automatic transmission. The friend says that the car ran fine before he parked it, so I'm hoping that it is just an adjustment somewhere.

>>

In a 4cly.. The direct spray into the opening of the pvc hose would go across to hit the Egr valve. Seafoam works well while soaking for a period of time. Then ulimately it would be sent out of the intake immediately. The pvc hose is directly in front of the Egr valve. Seafoam is a good cleaner for throttle bodies also allowing them to soak & to scub with an old toothbrush. I had discovered it through Toyotanation.com. They have a search that could answer your questions. It does many different things. It works suprisingly well.

>>>

I guess I'll have to check it out if I ever have a problem with carbon buildup somewhere. I clean throttle bodies with carb cleaner and a paper towel, it has worked well up to now.

No, the 4cyl DOES NOT have a EGR lift sensor. It uses the less reliable MAP vacuum drop and doesn't always catch low flows. Looks like you got lucky!

The carbon will blow out the exhuast pipe. As for intake it may be a small buildup in the small egr hole on the side of the manifold shouldn't be a problem.

Today I removed the EGR valve, there was some carbon, but not much. There was only a think layer of carbon. I cleaned it up. I did reset the light, and now waiting to see if the light comes back. If the light comes back, does it necessarily mean that a new EGR valve will solve it? Thanks.

Did you also clean the tube between the exhaust manifold and the EGR valve? The tube, especially where it connects to the exhaust manifold, may be clogged and you will get the same trouble code.

If the check engine light illuminates again, then you should check the trouble codes again because it is possible that the same or a different fault is causing the light to come on.

If you get the same trouble code (P0401), then the diagnostic process is pretty much the same. A replacement EGR valve may or may not solve the problem because the EGR valve may or may not be the cause of the check engine light. If you are willing to replace a part even though the parts replacement may not solve the problem, then you can replace the EGR valve.

You really need to borrow a MityVac vacuum pump/gauge from Autozone (free with deposit) to diagnose the system. The problem may be insufficient vacuum to open the EGR valve and not the valve itself.

So the EGR valve itself may be fine and if so you shouldn't spend nearly $200 to replace it. I don't believe in swapping parts to fix a problem, because it's easily turns into a good way to waste money.

If you borrow the MityVac then you can do two things and try to isolate the problem to the valve or modulator side:

1. Connect it to the EGR valve's vacuum port. Pull vacuum with the MityVac while the engine is idling. The engine should stall. This will easily confirm that the valve is working.

1. Connect it to the hose that goes to the EGR valve's vacuum port and measure the vacuum with the engine warm. Do you read increasing engine vacuum at the hose when opening throttle past 2500 rpm?