It is definitely possible to have small air leaks that cause lean running, but not so lean that the ECM cannot correct for it within its +/- 25% control range. Exceeding that range triggers the DTCs. Reading your fuel trims, if possible, may give you some clues.

 

Don,

I pulled my iCarsoft i930 scanner off the shelf this morning and spent some time reviewing the rather skimpy owners manual since it has been quite awhile. I figured out how to get to the live stream data so I warmed up the engine to normal operating temperature and was able to pull up the following information, all at engine idle of around 650 rpm:


Long term fuel trim bank 1 = 136%

Long term fuel trim bank 2 = 133%

Short term fuel trim bank 1 = 123%

Short term fuel trim bank 2 = 127%

Short term fuel trim bank 1 downstream = 128%

Short term fuel trim bank 2 downstream = 128%

Oxygen sensor equivalence ratio bank 1 upstream = .98% (that is decimal point 98%)

Oxygen sensor equivalence ratio bank 2 upstream = 1.01%

Canister close valve monitor - vapor recovery system = On

Canister close valve - vapor recovery system = Off

Evaporative emission system monitor = Test not complete

Exhaust gas recirculation target position = 0



I was not expecting to see percentages associated with the fuel trim readings....

What does all of this information indicate to you, and what should my next steps be?

Thanks for your kind assistance....

 

Next step is to find another reader. Those do not make sense.

 

Dale,

Do you have a scanner that can read the required data accurately? If so, would you be willing to take a few minutes to read Jan's car at your convenience?

As I mentioned before, this iCarsoft i930 has always been flaky....

 

Yes, no worries. Have several things, could also loan you one if you need it for some time,

 

Those readings may be equivalent to +36, +33, +23, +27, +28 and +28 on other scan tools. This assumption is based on the idea that a stoichiometric AFR would represent fueling of 100%, and any increase or decrease in fueling would be indicated by percentages above or below 100%.

But if your engine really was running that lean, prompting the ECM to add significant extra fuel, you would almost certainly have P0171 and P0174.

So take Dale up on his kind offer and try one of his scan tools.

Cheers,

Don

 

Dale,

Thanks for your kind offer. What timeframe works for you? I will bring the car to you and hopefully we can get accurate readings in 30 minutes or less....

 

Apologies for the delay in responding, touring NC during this lovely spring day that happened in the fall.

Tomorrow around 2 (sunday) is great, also next sunday around 2. Talk soon.

 

No need to apologize, Dale. I figured you were out enjoying the gorgeous weather. Always hard to beat early November here in central North Carolina....

Today at 2:00 pm works for me if it still works for you - let me know....

Much obliged....

 

Talk then.

 

Thanks Dale. See you at 2:00 pm....

 

Don,

Dale was kind enough to allow me to stop by this afternoon so he could use his much more sophisticated scanner on my wife's 2006 XK8....

All fuel trims were normal (at or close to 0) and the only pending OBDII code was the expected P1000. We do not suspect any air leaks....

In talking through my recent drive cycle efforts in my attempts to clear the various readiness monitors, I mentioned that I have been going through the code-clearing steps with my generic scanner just as a matter of starting with a clean slate before every drive cycle. Dale felt that doing so may be working against me by causing any previously-cleared monitors (such as the EVAP system monitor I managed to clear with the long drive cycle early last week) to also revert back to Incomplete status. Do you agree that this may indeed be wiping out my previously-successful monitor drive cycle attempts?

 

Stop clearing DTCs and don't disconnect the battery!!!!!!!!!!!!!!!!!

Either of those things cause to system to START ALL OVER AGAIN!!!!!!!!!! (P1000)

 

Dale and Bob are right!

Leave all completed readiness monitors complete unless you have to clear a stored Powertrain DTC that may prevent one or more readiness monitors from resetting.

Clearing any Powertrain DTC will reset all of the readiness monitors.

Cheers,

Don

 

It is mandated by law that clearing DTCs also clears all monitors....

 

Thanks to all for confirming that I need to complete the readiness monitor-clearing drive cycles before clearing any more OBDII codes. Sure wish I had known that a couple of weeks ago....

Now, back to driving the car and hoping not to get run over by a semi while coasting to a stop and idling for several minutes....

 

Good news....

About 30 miles of the various specific drive cycles on mostly empty rural roads and one somewhat busy highway this morning cleared all except one readiness monitor. My generic scanner calls it the "Comp. Component" and shows its status as "Incomplete". Anyone know what it is? I have never seen that term in my JTIS documentation....

Also, my generic scanner still shows the only remaining OBDII code to be P1000. I hope that a bit more driving will finally result in a P1111. I am not about to attempt to clear that P1000 code with my scanner because I fear that action would once again cause all the readiness monitors to revert back to Incomplete status. I assume I will get the P1111 code only when the car finally decides it is due....

 

DTC manual for 03 on says:"To avoid unnecessary complexity, a single comprehensive engine management drive cycle has not been developed for XK-TYPE. Refer to the individual DTC for specific drive cycle / monitoring conditions."

But since you still have P1000, it doesn't think it's done. On the other hand, NC probably does.

Note added: so it may well be the expectation of your obdii device, but not accurately reporting what's left.

 

YOU cannot clear a P1000.
The readiness monitor will change that to a P1111 when all are complete.

Either DTC P1000 or P1111 will always be present in the ECM!!

P1000 circle of insanity

The P1000 code is present when the ECM has had all DTCs ‘cleared’ from the non volatile memory or the battery power to the ECM is interupted.

The P1000 is changed to P1111 when the readiness monitors are completed by a specific ‘drive-cycle'.

People often see the P1000 DTC and try to clear it. This resets the DTC to P1000. (again)

Then the car is driven until the monitors change the DTC to P1111. (some guides reference this as a fault with the intake air temp sensor)

Jaguar P1111 is just the ECM ‘being-happy’, not a fault.



People see the P1111 and decide it must be a fault and clear the DTC.

The ECM now defaults to P1000 and the circle of insanity continues.

Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.
Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.
Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.
Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.
Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.
Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.
Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.
Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.
Then the car is driven until the monitors change the DTC to P1111.
The code is cleared and it reverts to P1000.

 

Thanks for the additional information, guys. I will continue to exercise the car and hope to see a P1111 soon....