Code P1491 EGR Sensor, took the rig in 1 month ago. they did not find anything other than perhaps a little carbon buildup in the valve.

Cleaned it, cleared the check engine light.

3 weeks later, check engine light back on, "same code, reset, tested EGR circuit, and valve function, could find no problem. Could be a problem with the ECM or Wiring,, could not duplicate customer complaint. Cleared code, and test drove. " (from the mechanics report. )
The vehicle has absolutely no symptoms, accelerates fine, runs smooth, shifts smooth, stops smooth, the gas cap is on tight, Any suggestions?

The only other thing, is during the last service, they did not reset the service notice light, and am wondering if that could trigger the check engine light?

Thanks.

 

If your mechanic isn't willing to try to pinpoint the problem, you should find another. Even if it is a dealership.

With that said, it's usually caused by a broken vacuum line. buy a can of throttle body or carb cleaner, and spray it in the vicinity of the EGR valve. If idle changes (stumbles or increases) then find out exactly which one is leaking. If that's not it, it very well could be a faulty diaphram in the EGR valve, which would warrant a replacement.

 

P1491? EGR valve is sticking once in a while. COMMON for this vehicle. Honda even has a TSB out on this. Replace the EGR valve with an updated honda EGR valve. For a P0401, the TSB also instructs you to remove the upper part of the intake manifold and clean out the EGR passage, drill it larger, and install a stainless steel passage tube.

 

Here's the TSB on the Extended Warranty on the EGR. For your 2000, you do not just replace the EGR valve. See details here: http://www.in.honda.com/Rjanisis/pubs/SB/A05-026.PDF

 

READ my post. It says drill out the intake. The TSB is for two failure codes, P1491-EGR lift. P0401-EGR flow.

 

Completely wrong and unfounded.