No readings on bank 1 sensor 2....

[JPrahl]

I’m still chasing the cause of my P0443 and P0403 code. I have checked and repaired the wiring harness, checked all ground points. Changed egr valve, purge valve....

Tonight I noticed that that I have no read out on short term fuel bank 1 sensor 2 and bank 2 sensor 2 can this be a possible cause?

 

[imp]

@JPrahl Possible partial blockage of cat converter, bank 2 (driver side). How many miles on the cats? imp

 

[JPrahl]

My 2008 Explorer has 110000km..
Thanks!

 

[JPrahl]

Just to confuse me even more so came P0645 on to the list AC works fine so where should I start??

 

[imp]

Just to confuse me even more so came P0645 on to the list AC works fine so where should I start??

@JPrahl
OUCH! Well, the first four, HO2S, Heated Oxygen Sensor heater, all four sensors bad at once? NO WAY. Two are fed by one fuse, the other 2 by another fuse, in the event the downstream sensors (farthest from the engine) are giving wacky outputs compared to the upstream, the "heater" codes are thrown. First thing is to check the sensor heater resistances using an ohmmeter; if I recall correctly it should be around 8 to 15 ohms, check to Ground also, should be extremely high (infinite).

EGR Valve Position indicates the EGR valve is either malfunctioning (mechanical problem, or the circuit checking it is haywire (DPFE Sensor). Enissions-related, won't upset operation much.

Purge valve: periodically allows charcoal canister to dump fuel vapor collected into engine to be burned. Little consequence.

OBD readiness test not completed. Can't help you there. I'd ignore for now.

If you can determine, one way or another, that the O2 sensors' heater circuits are receiving power, when they should (they're turned on by the PCM [computer], and have correct resistance, I'd go to the cat converters, again. imp

 

[JPrahl]

Thank you!! I do agree that all 4 sensor cannot be faulty but what “concerns” is that I don’t have any readout short term fuel on the both downstream. I do have volt readings on all 4. I also noticed that the engine light comes on when the engine reaches normal temp during cruise. So I think the egr valve doesn’t open.....

Do any of you know where I can hold of a engine wiring diagram for 2008 explorer?

Thanks

 

[imp]

Thank you!! I do agree that all 4 sensor cannot be faulty but what “concerns” is that I don’t have any readout short term fuel on the both downstream. I do have volt readings on all 4. I also noticed that the engine light comes on when the engine reaches normal temp during cruise. So I think the egr valve doesn’t open.....

Do any of you know where I can hold of a engine wiring diagram for 2008 explorer?

Thanks

@JPrahl
If still available, try Helm, Incorporated.

Ford Explorer 2008

However, it appears a Shop Manual is no longer available. Surely, one will be for sale on Ebay. The wiring schematics are extensive, in early 2000s, they were a separate publication, wiring only, softbound 8-1/2 X 11, several hundred pages, maybe a hundred bucks. I have one for every vehicle, wouldn't be without them. imp

 

[410Fortune]

it may just be your scanner, not all PCM and scanners will show real time switching of the downstream sensors....just FYI You will see 0% or no data for 2 downstream sensors, does not actually mean sensors are bad it just means the computer does not send that info to the scanner....

something to think about. Try your scanner on another similar truck? see if its the same?

 

[JPrahl]

Thank you guys! Today I came back from a China trip and put my head straight into my lovely Explorer. I found a wiring diagram last night which I study on the flight. So I took my multimeter and start to measure around. Everything seems to be okay (obviously not..) Egr valve seems to be stuck closed because the fault codes does only pop up when the engine reached normal temp during cruise. So today’s questio. Which pin should I ground on the egr to force it to open?

 

[imp]

T So today’s questio. Which pin should I ground on the egr to force it to open?

I believe the EGR valve is opened and closed by vacuum. That vacuum is controlled by a solenoid which acts on a diaphragm, which mechanically opens and closes the valve. The DPFE sensor tells the PCM how far the valve is open. The valveb being mechanical and exposed to heat and exhaust crap, can become jammed mechanically, either open, closed, or half-way. DPFE alerts to that. \

I check EGR valves by attempting to blow air through the valve, none should go through, then drawing vacuum on the diaphragm, which should open the valve, allowing air flow through. Applying then stopping vacuum, while inlet is kept sealed will reveal if diaphragm leaks. imp