Do you have a vacuum gauge?
Also, if you're measuring the DPFE voltage, the voltage between pins 27 & 46 should be less tha 0.2v and you're getting almost 0.6v - the manual says to replace the PCM at that point, but you've already done that so that makes it a little more complicated. Anyway, I was going through the steps and from here....according to the shop manual, you're supposed to start checking the EGR valve and DPFE sensor with a vacuum gauge.
Key "OFF".
Disconnect vacuum hose at EGR valve and plug end of hose.
Connect a hand vacuum pump to the EGR valve.
Apply 34 kPa (10 in Hg) of vacuum to EGR valve and release while observing movement with inspection mirror if possible. Look for binding of the valve pintle.
Does the EGR valve function in a smooth manner?
NOTE: Repeat test as necessary to ensure accurate results.
Yes -- Go to DL97. See: DL97 - Check EVR Solenoid and Hoses
No -- Remove and inspect the EGR valve for signs of contamination, unusual wear, carbon deposits, binding, and other damage. Service as necessary (use Rotunda EGR valve cleaner 021-80056 if needed). Clear continuous memory. See: Reading and Clearing Diagnostic Trouble Codes\Clearing Diagnostic Trouble Codes
DL97 - Check EVR Solenoid and Hoses
An EGR Vacuum Regulator (EVR) solenoid that is not functioning properly can cause the EGR valve to open or remain open when EGR is NOT demanded (such as at idle).
Key "OFF".
Inspect the EVR solenoid vacuum hoses and solenoid closely for the following:
Restriction in the vacuum hoses.
Signs of contamination, icing or moisture at EVR and in hoses.
Excessive contamination in the EVR filter.
Is a fault indicated?
Yes -- Isolate fault and service as necessary. Reconnect all components. Clear continuous memory. See: Reading and Clearing Diagnostic Trouble Codes\Clearing Diagnostic Trouble Codes
Rerun quick test. See: Reading and Clearing Diagnostic Trouble Codes\Reading Diagnostic Trouble Codes\Quick Test Appendix (Detailed Testing Instructions)
No -- Reconnect all components. Go to DL98. See: DL98 - Check EVR Solenoids For Shorts
DL98 - Check EVR Solenoids For Shorts
An EGR Vacuum Regulator (EVR) solenoid or EVR driver circuit short could cause the EVR to open supplying the EGR valve with vacuum.
Key "OFF".
Disconnect vacuum hose at EGR valve and connect hose to a vacuum gauge.
Run engine to operating temperature and stabilized idle.
With the engine at idle, tap the EVR solenoid and wiggle the EVR connector while noting vacuum reading.
Does the EGR vacuum remain below 3.4 kPa (1.0 in Hg) with no sudden increase?
NOTE: EVR leakage below 3.4 kPa (1.0 in Hg) is normal.
Yes -- Leave vacuum gauge connected. Go to DL99. See: DL99 - Check EVR Harness Circuit For Intermittents
No -- Inspect EVR solenoid connector for shorts. Service as necessary. If OK, service or replace EVR solenoid. Reconnect all components. Clear continuous memory. See: Reading and Clearing Diagnostic Trouble Codes\Clearing Diagnostic Trouble Codes
Rerun quick test. See: Reading and Clearing Diagnostic Trouble Codes\Reading Diagnostic Trouble Codes\Quick Test Appendix (Detailed Testing Instructions)