I have a 2000 chevy blazer, the check engine light is on. Code is P1404, EGR temperature sensor circuit, how expense and how difficult is it to replace, or can I just clean it and can a 'lay' person do it, or do I need to take it into the shop?
The code you have stored indicates that the Exhaust Gas Recirculation (EGR) valve is not closing completely when it is commanded off. (there is no such component as an EGR temperature sensor, despite whatever code reader tool you have may have said).
Usually this code is caused by a chunk of carbon deposit or other foreign material becoming lodged in teh valve, preventing it from closing. If there is no foreign material in teh valve then it may be due to a defective EGR valve, but this would be unusual; 99% of the time it is a piece of carbon causing the valve to not seat completely. Often, this will be accompanied by a rough engine idle condition due to the internal intake vacuum leak caused by teh valve remaining partially open.
I would suggest removing the EGR valve, turning it over, and inspecting it for any foreign material. If any is found, remove it and reinstall the valve. Clear the stored failure code from memory (either using a scan tool or by disconnecting the vehicle battery for a minute). Then, restart the vehicle and take it for a test drive to make sure the code does not recur.
This is something you can easily do yourself, provided you ahve average mechanical skills and basic hand tools (socket set).
Here is what the valve looks like, and it's location:
IMPORTANT: Note the orientation of the EGR valve at the BASE before removing. Do not use the electrical connector as an indication of valve orientation. It is possible to install this EGR valve backwards. An EGR valve installed backwards may cause a rough idle and set DTCs.
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25+ Years experience as a professional working automotive technician; ASE L1 master technician