It is being over-analyzed. E049 is a simple air management problem, the players in the game are the combination(diverter)valve, and the ecm. Included is a description and fail conditions for the E049. It would be a simple diagnosis for the right person, enter the on-board feature your vehicle is equipped with, excercise the EDV(divert solenoid), and the ESV(switching solenoid) that are all part of the valve itself. Does the airflow from the pump change respectively? From there the valve is condemned, or the switching signals from the ECM are then checked, and based on the result, the ECM is faulty or you have a possible wiring problem. You are going to spend more money running these other 'checks', rather than having the simple test from the fault code chart performed. The fault chart has two possible failures, the valve and the ECM. There is also wiring, and plumbing to check. The reason the car starts, runs well, and have no issues, is that this is just an emission control device that is at fault. Would you pass state emissions test(if you have it), that is another story, and that is why you would be obligated to put forth the effort in repairing. You want to narrow down possible causes, but you seem to be avoiding the potentially obvious cause, the valve. It seems to me that others are telling you what it COULD be, rather than testing for the smoking gun. My next two to three educated guesses are: function test the valve, and function test the valve.
This diagnostic test monitors the AIR system to detect operating problems with the Electric Divert Valve (EDV) and Electric Switching Valve (ESV). It performs these tests using the oxygen sensor and ECM integrator function to monitor valve function. This switch valve has a 2 pin connector and is located behind the cruise control servo bracket. The divert valve also has a 2 pin connector and is atop the AIR switch assembly.
TEST CONDITIONS :
Codes E013, E014, E015, E021, E022, E024, E031, E032, E034, E044, E045 not set.
Coolant temp between 80 C and 110 C.
Closed loop operation for 9 minutes, oxygen sensor ready.
Engine speed 400 RPM or greater.
Vehicle speed 0 MPH.
FAILURE CONDITIONS :
The ECM fails to detect an increase of 15 or more integrator counts, when AIR system diverts to the exhaust manifold.
System has failed test 4 times.
ACTION TAKEN :
ECM illuminates "SERVICE ENGINE SOON" telltale for entire key cycle.
AIR system is placed in divert.
NOTE ON INTERMITTENTS :
If code E049 is stored as a history code, verify oxygen sensor operation using Chart A-7. Check the operation of the AIR system using Chart C-7. Check all connectors, hoses and pipes for proper connection, corrosion, or damage.
Images (Click to enlarge)
Saturday, November 26th, 2011 AT 4:57 PM