EGR gas temperature sensor

[super_copy]

Hello,

I am going through a checklist of tests for a DTC P0401 on my Corolla. I can't find the EGR gas temperature sensor. Is it near the other EGR components, accessible from the top, or do I have to dig the underside of the car?

I uploaded a few pictures taken around the EGR valve, using a mirror, since I believe the temp. sensor should be very near it:
http://photobucket.com/CorollaE100_EGR

One of the pictures is a scanned diagram from a Haynes manual (for my specific car model) that I borrowed. I saw nothing that looks like the temp. sensor. The diagram seems to depict the sensor plugging into right under the EGR valve. Problem is, (what I think is the) the EGR valve from that diagram does not look like the EGR valve in my car.

Also, the vacuum hose routing diagram under the hood does not show the gas temp. sensor, but I'm not sure if it's because the sensor has nothing to do with vacuum/air ducts, or because there is no sensor?!?!

The engine is an automatic 1.6 L, if it matters. Thanks for any help!

[JesusJones]

I don't think our little simple 1.6 liters have a temp sensor for the egr. That was probably a feature that the 1.8 liters had. I recently had my egr valve removed so I could clean it out. No wires or sensors there. So for sure it's not in the actual egr valve. Maybe in the block somewhere.....

Cheers

[Dirty Dude]

You didn't say what year, but since an OBDII code was mentioned, I'll assume it's a '96 or '97. My '96 doesn't have a temp sensor in the EGR valve. From what I can tell, it doesn't have one at all. That's the thing with Haynes and Chilton manuals; they're cheap for a reason.

Your code for insufficient EGR flow is probably caused by the EGR valve failing to open, either from a punctured diaphragm or it's simply stuck with carbon and can probably be cleaned out.

[super_copy]

Just giving back some information to this very helpful community:

My problem was the vacuum modulator (aka vacuum regulator valve). I replaced it and have been driving trouble-free for a couple months.

I confirm the following key points discussed in the thread
96 corolla with p0401 check engine code

1) What user "kevmac" said about Haynes manual: the testing procedure for checking the vacuum modulator is insufficient. I suspect this test only checks whether it is clogged inside. My modulator passed that test (I blew air into it, and saw air come out the specified ports), but was still defective.

2) What user "msrdude" said about applying vacuum to the bottom port. My old modulator did not hold vacuum, the new one does perfectly. This test checks whether the diaphragm inside the modulator is cracked/broken.

3) What "Dirty Dude" and "JesusJones" replied: there is no EGR gas temperature sensor in the 1.6L engine car.

Once again, many thanks to the people who replied, and who posted their experiences in other threads!