1996 Toyota Pickup Code P0402

1996 TOYOTA PICKUP
116,000 MILES • 4 CYL • 2WD • MANUAL
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DAVEFRMCA
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I have the P0402 code. I understand it's an EGR system problem. I tested the EGR valve, using vacuum to the valve and the engine dies. It works OK. I tested the VSV switch and it's operating. I assumed it would then be the vacuum modulator so I replaced it. The ligh came back on in about 25 miles.
Do you have any idea what the problem might be?
Thanks
Dave Van Buren
Apr 3, 2008 at 1:56 PM
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MERLIN2021
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Causes. EGR stuck open, EGR VSV, EGR VSV open circuit, EGR temerature sensor short circuit, or ECM, Or ECM power and ground circut propblems... To check the temp sensor cicuit, you need a scan toll that can read the EGR gas temps, if the temp reads 318.7 Degrees F there is a short in the temp sensor cicuit. This is on a warm engine of course... disconnect EGR temp sensor connector, If reading is 37.6 Degrees F replace the sensor... If it is not you need to test the wires between the sensor and the PCM, if they test OK replace the PCM!


https://www.2carpros.com/forum/automotive_pictures/62217_TestEGR_1.jpg


https://www.2carpros.com/forum/automotive_pictures/62217_TestEGRa_1.jpg


https://www.2carpros.com/forum/automotive_pictures/62217_TestEGRb_1.jpg


https://www.2carpros.com/forum/automotive_pictures/62217_VSV_1.jpg

Apr 3, 2008 at 2:12 PM
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DAVEFRMCA
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Thanks for the info. I checked the ohms at the temp. sensor. It's 136 cold and 94 hot. There is 5 volts at the terminal when engine off.
Does this sound like temp. sensor?
Apr 3, 2008 at 8:33 PM
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MERLIN2021
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You want to check the degrees if you can...with a scanner that reads sensor values...Reading Ohms I think the value should be 2500! So yes I would say the sensor is No good!
Apr 4, 2008 at 12:29 PM
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DAVEFRMCA
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Thanks for the info so far. I found that I have a cracked exhaust manifold. Would that give me the P0420 code?
Thanks again
Apr 5, 2008 at 5:06 PM
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MERLIN2021
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Well I would fix that and reset the light first, but the resistance is still way off on the semsor. But who knows, you might luck out...
Apr 5, 2008 at 8:10 PM