Lots of faults are 'two-trip' DTCs.

Bob,

Do my multiple start-ups and shut-downs earlier this morning count as "two trips"? Or do I need to actually drive the car for several miles to count as a trip?

I appreciate your input. It is certainly worth taking the car on multiple trips just to see what happens....

Hi Jon,

I don't know how extensive the pinpoint tests are in the Workshop Manual, but I just took a quick glance at the Electrical Guide, and the circuit for the canister close valve power supply passes through Pin 4 of connector FH-1, which is a black 20-pin connector mounted at the lower right A-pillar. This is a common area for water ingress from a leaking sunroof drain, so it might be worth inspecting that connector for corrosion.

There is also a harness splice FHS4 upstream of that connector, but as usual the manual does not disclose its location.

I don't know if the pinpoint tests had you do this, but you could test for battery voltage on Pin 4 of connector FH-1 at start-up to be sure the voltage is within a few tenths of a volt of the voltage measured at the battery terminals. If there is a significant difference, you may have high resistance in that power supply wiring.

The other side of the canister close valve is the ground circuit through the ECM, and it passes through Pin 7 of that same connector FH-1. So you could literally test the canister close valve from that connector by attaching a 9-volt battery to pins 4(+) and 7(-); just be sure you are connecting to the valve side of the harness and not the ECM side. If the valve operates by applying power at that connector, the problem may be upstream.

There is an additional connector in the ground circuit for the valve, passing through Pin 29 of connector P141, a black 42-pin connector mounted in the engine compartment on the "passenger" side firewall/bulkhead.

If the pinpoint tests did not have you disconnect the ECM and check the resistance of the wiring to the valve connector, as well as for a short to ground, that would be worth doing, and you could also check the resistance between the valve and the pins at connector FH-1, as well as for a short to ground (a "high-resistance short," or in other words any resistance below infinity, can cause problems).

It would also be worth cleaning the ground points referenced by the ECM, (behind the right hand wheel arch liner on LHD cars), in case for some reason the ECM is more sensitive to high resistance to ground in the canister close valve circuit (I've seen this kind of thing many times).

Cheers,

Don

Don,

Thanks for your very detailed additional assistance. Based upon your newly-provided information, Dale and I will plan to huddle up again and pay attention to the various areas you described in your post above. In the meantime, I am going to do a few drive cycles (actually driving the car for a few miles at a time) WITHOUT clearing the icon and code to see if Bob's suggestion will get lucky for me....

I believe that P0447 is only evaluated in the first 10 seconds after ignition, and takes two cycles to report, so resetting the codes after this removes the annoying light only until the car is restarted a couple more times. Clearly Jon, some additional propitiation/sacrifice to the gods is necessary for this to go away for good...https://cimg0.ibsrv.net/gimg/www.jag...1d20d806a7.png

Actually, after clearing the Check Engine icon and P0447 code with my scanner, they come back EVERY TIME the engine is started. Not every other time. Nevertheless, as suggested by Don we have more potential areas to check when we are able to get together again....

I hope Bob won't mind... 2-trip is supposed to mean 2 warm ups (which has a definition in terms of how much ECT changed IIRC but is pretty much what you'd think is an engine warm up).

However, it may be that the fault is so definite that it can be flagged right away without needing the checks twice. (I forget what the actual standard & law mandate - neither's light reading.)

So, the pinpoint tests effectively check the system all the way back from the CCV connector (BT14)

1. Voltage on BT14-2 (high) to ground with ignition on (passes if > 10 volts, measured closer to line supply voltage)
2. Voltage on BT14-2 to ground with ignition off (passes if < 3 volts, measured zero)
3. Resistance from ECM EM80.67 to BT14-2 battery disconnected (passes if < 5 ohms). Will now do this next time. Who knew I didn't have a 5 point security torx to open the ECM connector? Who knew that the ECM needed a 5 point security to torx to 'secure' it? Who wonders what problem they were solving when they went from lever in earlier models to the uncommon security torx?
4. Voltage between BT14-1 (low) and ground (passes if < 3 V, measured zero)
5. Resistance from BT14-1 to ground (i.e. short to ground, passes if > 10kOhm, measured MOhms)

Interestingly, I also energized the solenoid which clicked on and off nicely. So, somewhat mysterious at this point. But cleaning the ECM ground couldn't hurt, checking the other points couldn't hurt, and perhaps it's 3...

Dale and I hope to be able to get together next weekend and resume Don's testing suggestions. So stay tuned, folks - more results to follow....

Many thanks to all who have contributed towards finally resolving this pesky issue....

Update:

Many thanks to Dale (crbass) for his persistence in tracking down the cause of that pesky P0447 code this afternoon. We started at the ECM and worked our way back towards the rear of the car, pulling the ECM harness, the glove box, some of the front passenger-side trim, some of the console, the back seat, and the fuel tank sheet metal shield in the trunk so we could get at the various electrical connectors along that path....

It took awhile but Dale found a complete ground wire break in the harness that leads from the bottom of the canister close valve up through the trunk floor and over to one of the connectors in front of the audio components stack in the right side of the trunk. About 8 inches up the harness that plugs into the canister control valve, that harness conduit had probably spent 15+ years rubbing against a bolt that it ran past. That friction had worn through the conduit sheathing, worn through the very small-diameter orange-colored ground wire, and then snapped it in two. Underneath the car my freebie Harbor Freight flashlight was not powerful enough to allow Dale to spot the break, but his much better flashlight finally revealed the problem. We pulled the electrical connector from the canister close valve, pulled that harness' grommet up into the trunk, and then pulled the entire end of that harness up into the trunk for much better visibility and access. So Dale actually soldered that ground wire break back together in the trunk, then wrapped that area of the harness in much stronger material than the OEM part came from the factory with. We then pushed the harness end back through its hole and pushed the rubber grommet back into place, then reattached the electrical connector to the canister close valve.

From that point we put enough of the car back together in order to test the circuit by starting the engine then shutting it down multiple times. The amber Check Engine icon never returned, and neither did the P0447 code once Dale cleared it with his scanner. I drove the 25 miles back home with no issues, did a couple more shut-downs and re-starts and presto, no more warning lights or codes....

No idea how long it will take me to clear the monitors by doing various test drives but I hope to start that process tomorrow (weather permitting). Who knows, it may take awhile....

Many thanks to Dale for his persistence and determination today. The problem is solved thanks to his expertise and equipment, and we had fun during the process....

And thanks to Don for his suggestions regarding where else to look besides the pinpoint tests specified in JTIS....

Congratulations, Dale, on a job well done!

Thank you, Jon, for such an excellent detailed resolution report!

I have added RESOLVED to the title of your thread!

Cheers,

Don

As always, the gods did not reveal the issue until Jon sacrificed by bleeding and we both spend sufficient time to propitiate whatever spirit made us not have the right five point tamper proof torx on his first visit. Thankfully, Jon took one for the team with grace (regardless of the alarm of my wife), and my bleeding was only metaphorical.

Twas satisfying to resolve.

Next time I run up against a difficult-to-trace electrical issue I will just go ahead and nick a finger with a razor blade and get the bleeding over with at the beginning of the diagnosis effort. That may save a ton of time....

Update:

I have managed to put about 75 miles on my wife's 2006 XK8 since last Sunday afternoon's successful P0447 / canister close valve wiring repair at Dale's house. Still have three monitors that need to clear. Any suggestions on specific driving patterns that may accelerate the process? We finally have early autumn weather in our neck of the woods which is making my random trips much more enjoyable....

Hi Jon,

See the readiness monitor Drive Cycles in the first 10 pages of the manual I am attaching. It's the DTC Summaries guide for the X350, but since your engine management system is the same, the drive cycles should apply.

Cheers,

Don

Thanks Don. I do not have WDS, but it appears that I need to do some moderate-speed driving (which I have done) along with some coasting (which I have not done). And then do some idling (which I have not done). I hope to incorporate all of these actions in some additional driving this week....

Remember to keep the fuel level between 20% and 80% for the EVAP test.

To expedite the process, follow the exact routine for each of the diagnostic readiness monitors that have not yet reset. The drive cycles are designed to prompt the ECM to run the tests you need to complete. If you rely on "some coasting" and "some idling," the tests may not commence or complete.

You can ignore the instructions regarding the use of WDS/IDS/SDD, but it will help to at least have some type of OBDII scan tool that can clear DTCs when so instructed in the routine, since monitors will not complete if even temporary DTCs are present.

If you have an Android phone, the Torque Pro app and a Bluetooth ELM327 OBDII interface is an inexpensive setup for reading and clearing codes and viewing Live Data and pending codes (including Mode $06 hexidecimal data). If you have an iPhone, DashCommand and a WiFi ELM327 is similar, but I do not know if it can read Mode $06.

Cheers,

Don

Thanks Don. I will follow the drive cycle instructions as closely as possible. Finding a long empty stretch of road to do the necessary coasting and coming to a full stop will be quite difficult, however....

Yes, that's always the challenge!