Diagnostic code P 1491 - Malfunction in EGR System. Check engine light stays on however ports were cleaned one year ago. Light stayed off until one week ago (6/1/10). What is code 1491 exactly.
Check engine light on 1998 Acura TL
The code P1491 is an EGR Valve Position Sensor code, not a code for plugged ports, so most of the time this means that either a piece of carbon has clogged your valve and it can't close properly or that the Position Sensor on the Valve is worn out. Best to have a savy tech do a scan of the EGR valve data to see if the valve is closing, any idle problems? A sticking valve may cause a rough idle, though the computer will compensate pretty well.
Thank you for this valuable information. I could not get anyone in ATLANTA to tell me this and finding a savy tech is going to be a task. No idle problems as of yet. Twice I notice a sputter while cranking in the morning. Will this cause the use of gas to increase?
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I believe you said that the diagnosis you received was a hold in a hose, which I believe can cause an EGR code.