I got this from Uncle Jim a while back. At the time my 22RE was not running that bad so if yours is I would suspect the EGR valve itself. It is simple to test as he describes below.


"Pete, Code 71 applies only to California vehicles and indicates a fault in the EGR temperature sensor circuit. The usual malfunction when this code is set is the EGR valve and not the temp. sensor itself. Really, the EGR temp. sensor is kind of the ECUs way of checking EGR flow by measuring the temperature of the exhaust gases and comparing it to set tables in the ECUs programming. Common causes for this are a bad EGR valve, EGR valve plumbing (vacuum lines and hoses from the EGR vacuum modulator and VSV), or a plugged EGR valve. More often than not, it is the EGR valve causing the code and this can be checked by applying vacuum to the EGR valve and seeing if the engine stalls or drops a significant number of RPMs (at idle). However, don't overlook something as simple as a split or disconnected hose or vacuum line or a bad vacuum switching valve (VSV). That's it for Advanced Code 71 lessons today"