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Toyotapro
Toyotapro, ASE master tech
Category: Toyota
Satisfied Customers: 9974
Experience:  ASE Certified, 10+ years Lexus and Toyota Certified
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FLOW..CARBON..EGR TEMPERATURE REPLACED APPLIED MANIFOLD..EGR VALVE

Customer Question

POWERTRAIN CODE P0402 EGR FLOW
EXCESSIVE DETECTED. EGR BEEN RNR
THROTLE BEEN REMOVED TO CARBON OUT VSV (VACUUAN SWITCH REPLACE FOR THE EGR. EGR TEMPERATURE REPLACED APPLIED MANIFOLD TO EGR VALVE CAR DIED.PCM BEEN REPLACED . P0402 KEEP COMMING BACK . I!M LOST . THANKS.
Submitted: 8 years ago.
Category: Toyota
Expert:  Steve replied 8 years ago.

Hello!

This code can be set by incorrect resistance in the wiring harness between the EGR temp sensor and the ECM. Try using an ohmmeter to check the harness for open circuits, excessive resistance, or a short to ground.

The easiest way to check the harness is to connect a scan tool that is capable of displaying live engine data, and checking to see what the EGR temp sensor reading on the scan tool is, and then comparing it to actual EGR temp measured at the sensor location. Then, checking to make sure that the temp reading changes when the EGR is commanded open is the next step.

Expert:  james replied 8 years ago.
possible causes are egr valve stuck open probably due to carbon build up in the intake/ egr temp sensor short in harness to ecm / or an ecm failure. the most common would be a carbon build up in the intake manifold holding the egr valve open . Hope this helps if so please accept and thank you for using justanswer.com james
Expert:  Steve replied 8 years ago.

The customer has already stated that he replaced the EGR valve, and that it has been tested and is operational. he has also stated that when the valve is manually opened the engine idle drops to the pointnwhere the engine stalls, indicating relatively normal EGR flow is present.

I just posted the information about the EGR temp sensor harness being the likely cause here, and the customer state the ECM has already been replaced.

Expert:  Steve replied 8 years ago.

hello;

How are you making out with your P0402 problem?

Expert:  Toyotapro replied 8 years ago.
Thank you for using just answer. For some reason this question was put into the Nissan category for nissan technicians to answer. It has now been moved to the toyota section by the just answer moderators, would you like some assistance with this issue? I am certified and experienced with Lexus vehicles as well as toyota.