2000 XJ8, recently replaced an ignition coil due to misfire. I've done this several times before for different coils. As always, I then clear the codes & do the drive cycle and eventually get the sought after P1111.

This time despite doing these Drive cycles several times and going on a bunch of trips I can't get the “CAT” item to complete. It still blinks when I ck with my OBD2 & is the lone holdout. I think this is the catalytic converter efficiency diagnostic test.

I think the drive cycle that is supposed allow this to run is driving for five minutes steadily at 55 mph or perhaps driving for five minutes between 1700-2500 RPM, which amounts to about the same thing. I've done both.

B4 I did the drive cycle, I I just drove on sone errands w/o following a specific cycle & got 3 of 7 tests to complete; MIS, FUE, HTR & the ones that did not complete were; CCM, CAT, EVE & O25.

So, I did this drive cycle:
=====================================
Drive Cycle (OBD-11)
A “drive cycle” carries out EPA diagnostics on all systems.
The drive cycle can be completed in approximately 15 – 20 minutes and is performed in the following 8 stages:
1. Cold Start
To qualify as a “cold start” the engine coolant temperature must be below 0°C and within 6°C of ambient air temperature. Don’t leave the ignition key on prior to the cold start or the heated oxygen sensor diagnostic test may not run.
2. Idle
The engine must be run for two and a half minutes with the air conditioner and heated rear screen ON. The heavier electrical load the better as this will test the O2 Heater, Passive Air, Purge "No Flow", Misfire and (if closed loop is achieved) Fuel Trim.
3. Accelerate
Turn off the AC and all the other loads and apply half throttle until 55mph is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
4. Maintain Steady Speed
Maintain a steady speed of 55mph for 3 minutes. During this time the O2 response, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
5. Decelerate
Lift off the accelerator pedal. Do not shift gear selector or touch the brakes. It’s important to let the vehicle coast, gradually slowing down to 20 mph. During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
6. Accelerate
Accelerate at 3/4 throttle to 55-60mph. This will perform the same diagnostics as in stage 3 above.
7. Maintain Steady Speed
Maintain a steady speed of 55mph for five minutes. During this time, in addition to the diagnostics performed in stage 4, the catalyst monitor diagnostics will be performed.
8. Decelerate
This performs the same diagnostics as in stage 5. Again, don't shift the gear selector or touch the brakes.
If the catalyst is marginal or the battery has been disconnected, it can take 5 complete driving cycles to determine the state of the catalyst.
================================================== =====
It mostly worked & 6 of 7 complete but the stubborn “CAT” remains incomplete & taunts me!

I have set cruise control @ 55 & timed it for 5 -6 minutes & still CAT not complete.

I also followed this similar drive cycle:
https://www.obd-codes.com/jaguar-drive-cycle


Any suggestions? I have to go through emissions next month.

Thanks!


Related thread for XK8:
“Readiness and the drive cycle”
https://www.jaguarforums.com/forum/x...e-cycle-66702/

 

Is this correct?

0°C is the freezing point of water. How could you ever manage that in Arizona?

Thanks for the procedure. Once I get the Knock Sensor replaced and the codes are cleared, I shall try to get that 1111 code.

Good luck with the Cat test.

 

Must be a misprint/typo.

I think that Drive Cycle (with the error "0°C" ) was from a Jaguar Forums PDF I D/L.

 

Some posted faults take up to 30 key on cycles, just drive the car, it'll eventually go.

 

I’m hoping.

 

The Drive Cycle for CATALYST EFFICIENCY MONITOR alone is:

1. Start engine and bring to normal operating temperature > 82 °C (180 °F).
2. Drive vehicle steadily between 1700 – 2500 rpm for 5 minutes.

If the other monitors are already complete, there is no need to go through the full sequence each time.

Graham

 

I was wondering about that. I had assumed that was true, thanks to your post I know it is. I've already done the five-minute drive at 55 and then on a different day drove watching to make sure the tachometer was between 1700-2500 RPM for five minutes. I'll try to do it every time I drive the car, which is not everyday. I switch off between two cars.

 

I disconnect my battery when I expect not using the car for a week or longer, so I start with a P1000 most of the time.
I
n my experience, the above drive cycle is far too rigidly described.
I have never in my life done a 5 min 55MPH steady speed, it's simply impossible here.

Still it always settles within ~15-20 miles, almost at the same point on the 55 MPH coastal, but hilly route.
Maybe some variation in stead of the steady ride will do the trick.

 

Today I drove the Jag & did several errands & was unable to go 55 (or 1750-2500 RPM) for 5 min., due to traffic. (As I mentioned, I DID do just that, 2 times, a few days ago ) Today, I drove at various speeds but, when I got home, I tested & still P0000, CAT has not completed.

 

Did any codes appear after your last clearance?
Did you check your fuel trims, short and long term?

Maybe it is not the drive cycle itself, but something else is preventing the CAT to settle.

 

Nope, only 1 “code” the P0000.

Do you have a link to how to check my fuel trims? Does it involve 2 people, one to drive & one to watch OBD2 live data?

 

Depends what you use to read your OBD data and codes.

I myself use a ELM327 for the plug in the driver's footwell, and Torque Plus on my Android phone.
It reads short- and long term fuel trims for each bank live, plus the functioning of many other sensors.

If your reader is able to provide live data, then search for STFT and LTFT, both should be available for each bank (so 4 readings in total).

These readings will give an idea if all is OK, or if you will need to check more data as a next.

 

It's not essential to follow the drive cycle but it can speed up setting monitors. The EVAP can be tough to set on some cars as a cold soak is commonly needed and tank between certain fill levels.

Every battery disconnect clears every OBD monitor and learned values such as fuel trims.

Fuel trims: first you need to let them learn and keeping disconnecting the battery will prevent that as it clears them each time. After the learn, which will take a few days of driving (so engine starts cold each time), get engine hot, then park. Watch LTFTs at idle then rev to about 2500 and watch again. 10-20 secs each time, they should be pretty stable. Then it's how they're different...

Is it really P0000? Sure it's not P1000? I never heard of P0000.

 

Oops, Meant to type “P1000.”

I use “Innova OBD-2 model 3130.”

After having my battery negative terminal disconnected for at least an hour while I changed out an ignition coil, my car STIILL had the several DTCs! I had thought they would be cleared but, no, I had to follow the erase procedure in my OBD2 manual to erase the codes.

Yes, my scan tool reads short- and long term fuel trims for each bank live. But, I don’t know what they should be or how this will help me.

If i have not achieved P1111 in a week or 2, I may attempt to check the STFT & LTFT. If I can figure to what exactly I’m looking for & how it may prevent the CAT test from completing.

 

Obviously you will never get P1111 if you keep disconnecting the battery.

LTFTs with hot engine should be near zero but you need to let them learn so stop disconnecting the battery (I guess you're getting the message). Be sure to check for air leaks using them.

It also makes sense to check sensors for plausibility (which tends to mean not many sensors since only some are obvious).

Any pending code can be a hint of something blocking an OBD monitor.

You can hit Catch-22: you had a problem you've lost (*) and now it can't set monitors so can't flag codes. This is fairly unusual but can be a nightmare.

(*) such as failed to write down codes but cleared them - this can be a big mistake

 

JagV8,

FWIW, I do not keep disconnecting the battery.

Only did it once to work on the ignition coils.

So, If I do not to get the CAT test to complete & achieve P1111, I need to see if the LTFTs with hot engine are near 0?

Is it OK to drive the car till normal operating temperature (hot) & then park & watch Live Data of LTFTs while idling? Or must I be cruising/moving while looking @ LTFTs?

BTW, I have always written down any codes.

 

Yeah, if you are uncomfortable checking while driving (), have the car hot, then check them.
On idle, they STFT should hover around zero, the LTFT should be within +/- 3% for an ideal engine, although the tolerances are much wider before an code comes off.

 

Drive to get it hot - yes, fine. It's just to be sure it's up to operating temp including cats.

 

Drove 30 min stop ~1 hr. & return 30 min. When got home ck & no change. CAT test still not complete. P1000!

Car @ operating temp So, hooked up OBD2 & ck live data for fuel trims.
Ignition on but engine off:
Fuel Sys1 OL
Fuel Sys2 OL


STFT B1 0%
LTFT B1 8.5

STFT B2 0
LTFT B2 0.78 (7.8?) my bad handwriting


Now with engine idling but parked:

Fuel Sys1 CL
Fuel Sys2 CL


STFT B1 2.3%
LTFT B1 8.5

STFT B2 2.3
LTFT B2 7.8

STFT B1 S2 -1.5
STFT B2 S2 -0.7

Now drive a few miles & park with engine idling:


STFT B1 -1.5%
LTFT B1 11.7

STFT B2 -3.1
LTFT B2 10.1

STFT B1 S2 -0.7
STFT B2 S2 -0.7
Note: the #s constantly changing!

Drive a bit more & then park & idle:
STFT B1 -0.7, -2.3, 3.1%
LTFT B1 9.3

STFT B2 -4.6, -5.4, -7.8
LTFT B2 8.5

STFT B1 S2 -1.5
STFT B2 S2 -0.7
Note: the #s constantly changing!

I don’t know the difference between B1, B2 & B1 S2 & B2 S2.

My STFT % seem to all be close to 0 but, my LTFT % readings vary much more. ~ 8-12%

What does this all mean? Does it have anything to do with the CAT test not completing?

No new DTCs just the P1000 not ready code.

Emission test due b4 6-15-2017!

 

I am travelling and on a mobile, but a quick view of ur values does not show too much abnormalities.
The long term ones are a bit high, but should not give codes, nor should prevent settling.

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