So posted P0455 & 456 a bit ago. Occasionally got the P0456, I'd clear it and would be fine for 1 to 4 months. Then pop up normally when I idled car for a fair amount of time after driving it. Thermo suggested in my post that removing the tube from the "what the frak it's called" sensor under the firewall o2 sensor plugs, cleaning it and reattaching might help.

So emission test needed to be done today for licensing. Had cleared the code a few days ago, but emissions had not yet reset for drive cycle on the initial station test. Showed "computer" & emissions not completed. So, I followed the advice Thermo gave on cleaning sensor, drove the car on another 150 mile trip. Checked codes at 30 miles, 75 miles and 105 miles in. No pending codes, but P1000 still there each time. Finished the balance of the 150 miles. Pulled into the emissions station, pulled codes before walking in and FK ME! had pending codes of P0171 & P0174 along with the persistant P1000 drive cycle not completed (again test station calls "computer")

Lean on both banks? Never had these codes ever. Fortunately, no MIL on, test station pulled it in, tested and they passed me, as it only had the P1000 (they call computer) showing and emissions and all the other tests passed.

Researched the codes here and did all the visual checks suggested, sprayed starter fluid on brake booster line (& mine has the sealed looking valve in the middle) both ends (it's a hard plastic tube) sprayed the other hard plastic tube from the "whatcha callit" sensor I had tried cleaning Thermo suggested, on firewall end and top right of intake. Sprayed the pcv (ribbed) both ends, sprayed the accordion air box tube both ends. Sprayed the outside of the MAF sensor (right behind the air box).

No change in r.p.m's or engine sound on any of these areas and while driving the car there was no hesitation or misfiring at all. Drove on the trip as normal as ever. The guidance on the codes seem to suggest it has to be one of these areas with a leak.

Any other guidance as to what to try or look for next? I have cleared the "pending codes" once more just for giggles to see if they come back the next time I drive the car.

 

You're mistaking P1000.

The test does not see P1000 and is uninterested in it.

What it sees is the status of each individual OBD monitor. They told you which of those were a problem.

Any unset monitor results in P1000 - which is a pending code and that is why the test place does not see it.

Any decent OBD tool can show you the monitors.

 

Dell, you didn't mention checking the IMT valve o-rings. After that, if you look under the intake, you should see green and orange (as I remember) plastic tubes. With age, these can get brittle and if you are moving stuff around in that area, they can crack, leading to what you are seeing.

After that, do you smoke or know someone who does? If so, get yourself a nice cigar and with a cold engine and the A/C turned off (including the defroster), start up the engine and gently blow the smoke into the engine bay. Watch the smoke slowly roll through the engine bay and see where it suddenly makes a sharp change in direction. That will point to your vacuum leak.

 

Thx Thermo, yes I did spray starter fluid on the imt as well (looking into the engine bay, left side (U.S. Passenger side) black plastic electronic pieces). I'll look today under the manifold for the tubes. I am assuming they are fairly easy to see looking into the bay?

Btw, tried blowing cigarette smoke in the bay yesterday, but you know sitting out in the open is just NOT conducive to the smoke wafting in there, lmao! I'll need to get it under cover to try that soon.

Just felt it was awfully strange to have cleaned that relay on the firewall (& was clean as a whistle to begin with) then have the lean situation suddenly appear on the next immediate drive?

 

Dell, that is why I bring up the colored hoses on the underside of the intake. With reaching back for that solenoid valve, you could have hit them. Also take a look to make sure that the vacuum line to that solenoid is on good. As silly as it sounds, what you messed with is most likely where your current problem is.

 

Ok, so looked for the "tubes" you mentioned. I see nothing like that on mine. I did remove and reinstall the sensor tube (push pin clips on each side, slide off, slide back on making sure it "clicked" in place again. With engine running and finger on the sensor, I can feel it "pulsing/clicking" so I assume it is functioning correctly. You can even faintly feel the pulsing when holding the hard plastic tube that attaches to the driver's side of the manifold. Rechecked all the lines for deterioration or splits/breaks = nothing apparent.

I took pics of the areas I looked in and sprayed starter fluid. Everything looks pretty darn clean and newish looking.

 

Odd, pics downloaded, didn't post




Sensor on firewall under the O2 plugs



Pcv & air box pics





Brake booster line to manifold, Note the molded plastic type bulb



IMTs

 

This is looking under the manifold for the "tubes" you mentioned. In the space in front of and below the firewall sensor and O2 plugs (they would be BNE in pic). I see nothing like you mentioned in that area.

 

NNE*

 

Could you maybe have triggered that by poking around while the engine was running and maybe momentary dislodging something just enough to trigger that code? To get a check engine light the condition has to be present two consecutive trips. Drive it a few times and see if the light actually comes on. If it doesn't and you clear the stored code and it doesn't come back chalk it up to just one of those things.

 

Lmfao, maybe - she told me not to poke her there.......

 

Dell, unfortunatley, I am not seeing the tubes in any of your pictures. Without having a car in front of me, I am going off of 3+ year old memories.

 

HI Dell, were you able to find the root cause of your issue for this? I've had the P0174 code appear three times now: once in December, once in March, then again this week. In March I took it to my Jaguar specialist and he replaced the MAF sensor and I asked him to change the fuel filter at the same time too. He's highly specialised in Jags and knew the code and fault by name when I called up, and checked it for vacuum leaks but recommended the MAF sensor as the probably solution. Would be good to have more info to go back with of other potential areas.

 

So, if you read this thread from start, it was not really addressing the P0456 or P0455 code faults. That being said, the advice Thermo gave me in my thread on P0455/P0456 codes seems to have worked for me (the removal and reattaching of the connection on the "valve" under the O2 sensor on firewall). After the odd occurrence listed at the beginning of this thread, I removed and reattached it again and no code yet.

Here is the original thread on the P0455 & P0456 =

https://www.jaguarforums.com/forum/x...-p0456-198025/

 

Dell: The "what the frak it's called" under the firewall O2 sensor plugs - that's called the Evaporative Purge Valve, aka Vapor Canister Solenoid. Google part number C2S8605.

Your Jag's Evap Purge Valve was stuck open, causing P0455 / P0456 error codes and pending P0171 and P0174 (lean bank 1 & bank 2). After you cleaned the Evap Purge Valve, it was able to close properly, solving the problem. Error code P0455 = large leak; P0456 = small leak. Thermo's suggestion to clean your Evap valve was spot on. A shot of carb cleaner inside the valve usually does the trick.

Prior to the 1980's, fuel tanks vented directly to the atmosphere. To stop this source of air pollution, carbon canisters were added in the 80's to capture vent fumes and comply with new emissions reg's. When the engine is running and warm, the ECM opens the Evap Purge Valve to suck air and fumes from the carbon canister (above the fuel tank on our X-Types) to the intake manifold and engine where they're burned. When the engine is off or cold, the Evap Purge Valve springs closed to trap fumes in the carbon canister.

This video explains how the Evap Purge Valve works. Not a Jag, but the concept is the same:

 

Correction: The purge valve solenoid part number is C2S11045, on the firewall. The vent valve solenoid part number is C2S8605, above the fuel tank.

This post explains how these two solenoid valves work together to reduce fuel tank emissions: https://www.jaguarforums.com/forum/x...2/#post1899154