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Ask Skyvisions Your Own Question
Skyvisions, ASE Certified Technician
Category: Toyota
Satisfied Customers: 14324
Experience:  Toyota Master Diagnostic
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Customer Question

Submitted: 4 years ago.
Category: Toyota
Expert:  Skyvisions replied 4 years ago.

Thank you for choosing JustAnswer and allowing me to help you resolve your Toyota questions!


How many miles and has there ever been any other codes set? Do you need an emissions test to get your plates renewed?

Customer: replied 4 years ago.
I recently repaired my 2001 tacoma 2.7L egr valve and modulator. Now I get a p0402 code, excessive flow. Do I need to replace the vacuum switching valve for the egr? Or the temperature sensor? Also I don't even know where the vsv is located.
Expert:  Skyvisions replied 4 years ago.
Are you 100% certain that you got the vacuum lines to the EGR valve in the modulator on correctly? If you disconnect the vacuum line going to the EGR valve then drive the vehicle do you then get a P0401 code? Does the engine appear to idle normally or does it idle rough as if the EGR valve is stuck open? Did you replace the modulator and EGR valve with new Toyota parts or the aftermarket or used parts?
Customer: replied 4 years ago.
150,000 miles. There was code p0401 and a catalytic insufficient. I also recently replaced the catalytic converter. The code has been cleared and didnt come on. The vacuum lines are connected correctly. And the valve and modulator were parts directly from Toyota. I read that if I don't warm up my truck in the morning long enough that the p0402 might reappear. The first time p0402 appeared was a couple days after the valve n modulator was installed and it was early in the morning about a block away from my house.
Expert:  Skyvisions replied 4 years ago.
Frankly I've never heard of this happening before that you have to let the engine warm-up for driving or this code will set. There are no technical service bulletins advising of this condition. That sounds extremely unusual. If the vacuum line that beliefs atmospheric pressure to the EGR valve by way of the VSC is restricted or the VSV is clogged it can cause the EGR valve to come on before the engine is warmed up. The computer can detect this and will flag 402 code as premature EGR activation. Make sure that you have airflow through the EGR valve VSC and the line going to the EGR bleed system. You have tested the sensor to make sure that it is functioning correctly also I assume.
Customer: replied 4 years ago.
I've been looking for replacement part for the vsv but cannot find it online. Do u have a part number for this model? Also if the lines are clogged, what is your suggestion to clean it?
Expert:  Skyvisions replied 4 years ago.
It's not likely that the line would be clogged if anything the valve itself is stuck closed not allowing air to get to the top of the EGR valve to bleed atmospheric air over there. Either that or the line could be pinched or collapsed. Do you have a vehicle identification number handy? With this number I can look up the specific part number.
Customer: replied 4 years ago.

part # for the vsv and temp sensor please
Expert:  Skyvisions replied 4 years ago.

25860-75060 vacuum switching valve


89412-34010 sensor for EGR exhaust gas temperature

Customer: replied 4 years ago.
Could there be any other possible problems that caused this code?
Expert:  Skyvisions replied 4 years ago.
Is not likely. Either the valve is sticking open or is coming on too early for the engine warm-up cycle.
Customer: replied 4 years ago.

what is the part # for the dpfe sensor?


Expert:  Skyvisions replied 4 years ago.
DPFE sensor?