I have an issue with the EGR valve on a 2001 3.8L Chevy Impala. I get the dtc P0401code, insufficient flow. I replaced the EGR valve with a new Delphi, removed the throttle body and checked for blockages, both at the EGR side, including the EGR, tube and inside the manifold. All were very clean. The reason I replaced the EGR valve was because when testing the pintle position voltage, I found voltages to increase somewhat steady, but then would move up or down one or two volts, then move up somewhat normally to 4v, then zero out for a split second, only to return to 4.15v, then continue up to 5v. The same happened pretty much when I slowly return the pintle position back to the original.866 volts. The range should be somewhere from the minimum voltage, .6 and move upwards to 4.5v. Mine went up to 5.04v. So, having such erratic readings, I decided to purchase a new one.
I installed a Delphi and the P0401 error code came back on. I rechecked the new pintle voltages and found that the voltages increased pretty steady as I moved the pintle into the valve, but when it got to 4v, it still zeroed out for a split second and then back to normal and increased to about 4.5v. Thinking that I got a defective EGR valve, I went over to NAPA and tested another new one, and the same voltage error, zeroed out at 4v. So, now I'm thinking it is either a defect in the design of the EGR valve, an issue with the PCM, an issue with my Fluke multimeter, or not an issue. Any ideas on this one?
Also, when I checked voltages, resistance, 5v reference and ground circuit reference points on both new and old, all seemed ok, except that when I tested the power (12v) circuit with the connector off, I would get the required 12v, but when connected and backprobed, it zeroes out (.02v). The manual states the I can probe either ways, connected or disconnected and should get 12v. I would think, when disconnected, and getting 12v from the PCM, this should be correct. That said, if taking the voltage reading when connected, the signal path/circuit seems to ground the 12v signal, and therefore I am not be able to get the 12v readings when connected to the EGR. This P0401 dtc is very puzzeling, to say the least. What is going on here?
have the same problem?
Friday, April 24th, 2015 AT 12:31 PM