Have 2006 escape, 3.0L, 2wd, Auto, a/c, 209k miles. Passes KOEO test, but fails KOER test. Kicks all these codes at the same time: P0135, 141, 155, 161, 403, & 443. I find it exceedingly unlikely that all these individual components have failed. I downloaded the service manual and proceeded with the pinpoint tests for the O-2 circuit, beginning with HO2S1-1. As directed in the manual, I started with test DW9. Failed. Manual says open circuit between connector and PCM. I started looking further at HO2S1-2. Failed same tests. Looked at the schematic. The signal and sensor circuits show as a direct line to the PCM, w/o splices or connectors in-between. The VPWR on all sensors go to Fuse #5, powered by the PCM Relay (fuse has power, so relay must be ok), and utilize Splice #111. Sensors 2-1 and 1-1 both go through splice #109, before joining with sensors 1-2 and 2-2 at splice #100. As there are also numerous other sensors that go through these two splices, and none of them have issues, I have to presume both those splices are ok. Vehicle starts/runs fine. The EVR & EGR circuits have no inter-relationships with any of the other fuses, splices, or connectors. I started to think faulty PCM, but much of the circuit continuity testing is done with the PCM disconnected, which takes that away as a contender. Anyone having any thoughts, I'm all ears. (My scan tool doesn't allow for active solenoid control, and has limited PID capability.)

 

Your analysis was going well up through the S111 reference, but derailed after that. Splices S100 & S109 are in the signal return circuit,

The VMV (aka CANP) and all four O2 sensor heaters run off fuse F05, the latter four via splice S111. The EVR valve is on a different circuit and should be addressed separately.

Start by verifying that circuit #34 (LB-OR) is actually getting and feeding power from F05 to each of its 5 loads. It likely is not. It could be that the fuse is blown, has a hairline crack in the fusible link, has bad contact pins or whatever.

As for the EVR, make sure that 1) its coil is not open, 2) it is plugged in, 3) it is getting power on the WH-RD wire, and 4) that there is continuity of the BR-PK wire back to the PCM.

 

SHO89:
Thx for fast response. I'll get back into it this morning on the power circuits. I may need to apologize, as in my initial post I mentioned the 'EVR', which the manual seems to reference being the Evap Purge Solenoid, but maybe I read that wrong. As I may, or may not, get the acronyms correct, in the future, I shall spell out the name of the component so as to avoid miscommunication. I did locate the Vapor Mgmt Valve being fed from F-5 on schematic 24-3, but also found an Evap Vent Control Solenoid on schematic 24-5, powered by F-27. So, to be clear, I'm going to be testing the Valve, not the Solenoid, powered by F-5. The Oxygen Sensors should prove to be more straightforward. You did mention a fusible link in the Valve circuit; I'm not seeing that listed. Where might that be located, please? You have been quite helpful, and I thank you.

 

That is the internal "link" inside the fuse shell. 5 of 6 of your fault codes indicate that the supply from fuse F5 is missing. Start there and VERIFY the fuse is actually passing power.

The "Vapor Management Valve" is also commonly known as the "Canister Purge (CANP) Valve" and is located under the hood. Don't confuse it with the "Evap Vent Control Solenoid" aka the "Canister Vent (CANV)" solenoid/valve which is located back on the canister under the truck.

 

Started at F-5. Have 12V on both sides of fuse. Have 12V to Vapor Mgmt Valve, EGR Control, and all Oxygen Sensors (grounding at battery). I went ahead and verified continuity of Signal Return circuits on all oxygen sensors to pin E-41 of PCM.

EUREKA!!! I found the issue in why I was getting a lot of open circuit readings! The schematic I downloaded, which is supposed to be the factory service manual has the oxygen sensor wiring/placement backwards! It shows oxygen sensor 1-1 wiring color codes congruent to what I have as sensor 2-1, and 1-2 as 2-2 - they're all reversed! No wonder I got so confused. I was just going by pin numbers and not noting the color codes. However, I would not have found this if not for your assistance - making me note colors and not just pins. Thank you so very much.

Being able to test properly now, I have continuity and voltages exactly where they should be. I've got a faulty PCM. I pulled it out and it was rebuilt once already in 2018, so, maybe the fix just didn't hold. I'll get a fresh reman unit and give that a whirl. Again, thx for your time and patience.