EGR MIL P0401, Code 71, engine check light, ad nauseam (long)


Mar 27, 2003
Groveland MA
I pride myself on my ability in this area and took that comment very personally.

A comment I have about your readings of the VSV is to be sure that you have the leads of your meter in the proper orientation each time. Part of any coil circuit is to have a diode placed accross the leads to make sure that the back EMF is controlled and passed to ground. The most common configuration is to have that diode mounted on the device. Since a multimeter calculates resistance by putting a small voltage on the positive lead and then comparing the amount read on the negative lead orientation with the diode can give erratic results. If you are sure that you have always had them orientated correctly then you might have a diode issue especially if the readings are less than descibed in the manual. In this case I'd repace the VSV because of potential damage to the ECM from uncontrolled back EMF. This won't help your CE problem but will help avoid a future failure of the ECM.
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