I have had little success with these "drive cycle" things. So many of them want you to drive at a steady 50 miles per hour, for 20 minutes, or whatever. Try that in SoCal and you'll become one with the front end of a Peterbilt. The cats should set up on a reasonably long freeway drive. If they don't, see above - you have some sort of problem.

 

This is why I swore that I would not buy a car built after 1970, LOL. I don't need my car, or its computer, telling me that I need to drive it more before it can reset the system that told me to change a relay after I've changed the relay. I have a similar issue with my wife's 2024 Hyundai Palisade. That computer told her that the left rear tire pressure was low. So I put the proper amount of air in the tire, checked it with my tire gauge. Now it will not clear the silly little picture in the middle of the dashboard screen showing the 4 tires with the proper psi until a sufficient amount of miles are driven, even though it knows that the tires all have the right amount of air pressure.

Joe

 

So after putting several hundred miles on the car at freeway speeds I took it back to the smog place. SAME ISSUE, incomplete codes!!! Is there anyone out there who has had the same problem? How did you fix it? Is this going to be a $2,500 trip to a dealership to "clear" the computer problem? Should I just drive it to my nearest dump and set it on fire? This is very frustrating to say the least. I wouldn't have minded it if it was one of the cars I bought just to have transportation but I actually like this car and enjoy driving it. Someone out there must know what the hell is going on here.

Joe

 

I'm now fighting the same problem as you. I was getting funky mixture errors on bank 1, but the monitor would eventually set after a long drive. I changed the upstream O2 sensor and the mixture codes went away, Unfortunately, no matter how far I drive, I can't get the monitor to set. I've been sidetracked with other issues, but as soon as I can I'm going to replace the downstream O2 sensor and see if that helps. If it does not, I'm going to install a "spacer" on the sensor and try again.

No, the "spacers" are not legal. However, in my experience, smog shops don't often check. I know mine doesn't. I found out I've had one on the E39 I've had for the last seven years, but the BMW ones are difficult to see.

 

Hey Y2K,

Where were you getting the mixture errors? The only "error" code I've ever go was the original code that I started this thread with, throttle motor relay off. I replaced the relay and poof the error went away. Now I'm not getting any errors, just the INC for the CCM, CAT and EVAP. The guy at the smog place said those mean that the system diagnostics will not complete but doesn't know why. What led you to the O2 sensors? Right now I have no "Check Engine" light or any other codes on my OBD2.

Joe

 

This is the document I’ve found regarding the “drive cycle procedures”. It appears to list “cycles” for several different component issues. Which, if any, of these "procedures" does anyone suggest to solve this problem?

 

Stupid question is are there any DTC codes present (scan for current DTCs, scan for pending DTCs). If there are not DTCs then it is perplexing.

The one I would be concerned about with is the "CAT", which I assume is Catalyst Efficiency Monitor. That should reset pretty fast if there are no issues, suggesting there could well be a problem with either the downstream or upstream oxygen sensors, etc.

The CCM (Comprehensive Component Monitor) will not complete if pretty much any of the "rest" of the DTCs are triggered or pending (i.e. not including any of the other specific component tests - misfire, oxygen sensors, adaptive fuel, EVAP).
The EVAP can be a pain to get to clear, for me it requires driving on the flat for an extended distance with a lot of coasting. There are a few threads with hints on this specific one (like not starting on a hill, tank 5/8 full, etc.)

The documentation is indeed pretty bad for the AJ27. There is this page at the start of the document on DTC summaries - OBDII, AJ27 Engine Management 2001 Model Year on (presumably US 2002 and on). Earlier versions don't have this page.


And then there is this on the 2003 version (but I think this is for AJ34 which has a completely different ECM, so whilst the spirit might be correct the details are probably not).







T

 

Hi Chirpy,

As I said the only code I ever got from either of my 2 OBD2 devides is the one that indicated "throttle motor relay off malfunction". That went away when I replaced the relay. Now it just won't complete running the checks and I get "INC" for the CCM, EVAP and CAT reading.

I'm going to try and run the cycle noted in some videos where the engine runs at 3,000 rpm for 3 minutes. I'm going to have to wait until late tonight to do the ones that require driving at 55 for a period of time and then coasting. Doing that in normal freeway traffic is next to impossible. I may have to set my alarm for 3 a.m. and head out, lol.

Joe

 

When I got mine back on the road it would set the CAT monitor, but it took an abnormally long time and I had to drive long freeway drives, like to San Diego and back. But, eventually, it would set. At some point it also started giving me mixture too rich codes on bank 1, but not enough to trigger a CEL. After some research it seemed it was probably a flaky upstream O2 sensor, so, while I had the trans out, I replaced that O2 sensor. From that point on, the mixture codes went away, but now my CAT monitor won't set. I've driven to San Diego and Tijuana multiple times, and nada.

OK. The CAT monitor will not set unless the computer recognizes a certain temperature difference between the upstream and downstream O2 sensors. If it sees that, the monitor will set. Conversely, once set, if it detects a "lack" of temperature variance, you'll get the dreaded "marijuana" code, i.e. 0420, cat inefficiency. My point is that if the CAT monitor won't set, and you've tried Cataclean and other chemical cleaners, then the problem is either a bum downstream sensor, OR a bad cat. Unfortunately, bad cat is more common. On these used heaps, one never knows what abuse the PO visited upon it. Running with a blown head gasket, running too long with misfires (that's why the computer cuts off those misfiring cylinders) or sometimes just high mileage. Anyway, you'll need some more diagnosis as to which cat is causing the issue. You can run the drive cycle until you're blue in the face and odds are that it will do nothing. Weirdly, you can drive forever and it won't set the CEL, but you'll never pass smog, either.

There is an alternative, and it's not legal in CA but many people do it. You get what's called a "spark plug non-fouler." Funnily, if you start looking for O2 sensors on Amazon it will come up with these things as "items others buy" with O2 sensors. For whatever reason, when you use one of these on the downstream O2 sensor, quite often it "fools" the computer into believing the cat is better than it is. My E39 has had one, on one cat, since I've owned it. I saw it when I was replacing the engine, but didn't know what it was.. A friend saw it later and said I must have a bad cat, look at the spacer. This car has about 240K on the clock now, and has never failed to pass smog.

Now on the EVAP thing, you do not need the EVAP to set in order to pass CA smog. And you do not need the CCM set, as I don't think it will set if the EVAP doesn't set. Others here probably know more. Anyway, the EVAP tends to be a huge PITA but fixing it is doable. On mine, the EVAP monitor would never set. And I'd get no CELs. One day, using a better scanner than normal, I found a code for the canister control valve open circuit, or something similar. That's the gizmo in the back. I replaced it and my problems started. NOW, when the car wanted to run the EVAP test it could actually try. And the next CEL light I got was for the purge valve malfunction. That's the one under the left fender. I replaced that and started getting "minor leak" CELs. Using the scan tool to close the CCV, I smoke tested the tank and found a leaky o-ring on one canister and (eventually) a crack in the other. After replacing the cracked canister (Yaaayy, NOMA) the EVAP monitor set, I get no CEL lights for EVAP anymore and all was right with the world until the CAT monitor refused to set.

Let me recommend that you do what I have done with other cars, and will do with my Jag as soon as time permits. You'll need access to underneath. Get the car up to operating temp by driving around a while. Get under it, while the car is running, with an infrared temp reader and read the temp of the cat's inlet and outlet. You need to see downstream temps somewhere between 100F and 300F greater than the inlet temp. This indicates the cat is doing its job. If you don't see that increase, odds are there's your bad cat. If a few doses of Cataclen don't help, then it's either time for a spacer or a new cat. OTOH, if you DO see a differential on both cats, then you may just have wonky O2 sensors, assuming you haven't already replaced them.

 

Again I'll wait to run the cat cleaner through the system and maybe put the new O2 sensors, whatever will let the CAT clear. If it doesn't I'll get an inferred sensor and take some measurements.

This is why I kept wanting to buy another old truck, and by old I'm talking pre 1965. No damn computer to tell me how many miles I need to drive at 3,000 rpms for 3 minutes and 24 seconds in order to let the computer know that I've changed the damn relay.

 

Yes, those are the things. There are shorter ones and longer ones. I have zero idea if the length makes a difference. IIRC the one on my E39 is the longer one, like the ones in your pix.

I have passed several cars with the EVAP not set. This Jag, a Chevy with a marginal cat that I used to own, a friend's Saab. I think even my E39, although the EVAP did set eventually.

With the exception of this Jag and that stupid Chevy, all of my cars' CAT monitors set up within at most 50 miles, and some as few as 20 - 30.

I think Denso 234-4798 are the downstream sensors and I see them available at many on-line parts stores, as well as eBay and Amazon.

 

If you have unset OBD monitors you should have (pending) P1000 but I don't see much mention of it.

If you don't always see one of P1000 or P1111 you need a better OBD tool as it's not telling you stuff. (What else is it not revealing?)

Your tool should also let you see exactly which monitors haven't set - hopefully a better display than the smog tool but that's adequate.

For every unset monitor a pile of codes can't flag. (Mainly because the car hasn't enough reliable data to know what to flag.) You can see a lot of info in Jaguar's OBD AJ27 Engine Management PDF.

Most drive cycles are just used to speed up the setting of monitors. But EVAP for example is awkward e.g. needs not too little or too much fuel.

Any time you need to drive huge distances to set something it really points to a sensor or the like being a bit or a lot out of spec.

 

Hi JagV8,

I purchased this OBD2 reader after reading numerous threads regarding the best one to buy for this car on this site:
It was said to be able to perform most of the function I would need for this car. It is the one I used to find the initial code indicated at the beginning of this thread.

When I plug it in now I do not get any P1000 or other codes.

It was suggested that I try a catalytic converter cleaner like Cataclean to clean the O2 sensors and see if that allows the codes to reset. Unfortunately I ended up having to have surgery a couple weeks ago and never got around to doing that. I'm going to pick some up today and run it through the system and see if that does the trick. If not the "Drive Cycle Procedure" information I've been able to locate for this car gives the following for "Heated Oxygen Sensors Monitor":Upstream (Universal) oxygen sensors:



1. Engine OFF; cooling fans inoperative > 20 seconds.

2. Start engine and bring to normal operating temperature > 82 °C (180 °F).

3. Drive the vehicle between 3000 – 4000 rpm at a steady speed. Lift foot completely off accelerator and coast to a stop within 30 seconds. Do not touch accelerator pedal for 4 seconds after coming to a stop.

4. Repeat step 3.

5. Idle engine for 11 minutes.



Downstream oxygen sensors:

1. Start engine and bring to normal operating temperature > 82 °C (180 °F).

2. Drive the vehicle steadily between 48 – 97 km/h (30 – 60 mph) for 10 minutes.

3. Drive the vehicle above 3000 rpm in 4th gear at a steady speed. Lift foot completely off accelerator and coast for 30 seconds.



Oxygen sensor heaters:

1. Start engine and bring to normal operating temperature > 82 °C (180 °F).
2. Idle engine for 3 minutes.

There is also a Cycle for "Catalyst Efficiency Monitor" which says to : 1. Start engine and bring to normal operating temperature > 82 °C (180 °F).
2. Drive vehicle steadily between 1700 – 2500 rpm for 5 minutes.

Do any of these sound correct to you? I've been driving since I'm 16 and have owned and operated dozens of cars, trucks and motorcycles. I've worked on my own cars and bikes for years. I've also worked for auto shops. I have never had to go through this kind of silliness just to get the vehicle through a smog check. I'm getting extremely frustrated and need to get this car's title transferred and registered. If there is something I'm missing could you please point me in the right direction.

Joe

 

These cars always have P1000 or P1111 as pending (status) code. Hunt around the tools menus to find those?

You should also be able to check which monitors are unhappy, again hunt around or someone may post how to.

 

I found the P1000 code on a different screen. I just started clicking on the different buttons and up it came. I've read through the instructions several times and there's no mention of this screen. I'm going to put the cat cleaner in and drive it for a while and hook the scanner up again and see if they clear.

 

So I've driven it another hundred miles or so and plugged the OBD2 in and NOW I get these crazy faults:









Sorry I think they went in backwards.
Despite the message about the "theft detected - engine disabled" I can still drive the car.
I guess I'm driving a stolen car around. GRRRRRRRRRRRRRRRRRRR!!!!

 

P1260 simply means the key RFID was not recognized at some point.

I get the DTC every once in a while on customer or my cars.

You might have turned the key and it not start the engine and turn it again and it starts.
You never really pay attention because it did start so you dismiss the incident?

 

These codes literally just came up today. I'm not dismissing anything, just pointing out what is going on currently. The last time I connected the OBD2 everything was fine except for the INC readings on the 3 monitors. This morning I got all the new codes. I'm an old guy so I apologize if I'm getting frustrated with a computer telling me that my car has been stolen. If the computer is so complicated that it determines that the car's original key in not the original key (or whatever glitch is causing the "theft" code) then maybe someone overdesigned it . Other than driving it to and from the store or gas station I haven't touched a thing and now I get all these codes.

 

The first thing to do is to double check your battery voltage at rest, and double check your alternator output while running. These cars kick out some seriously weird errors when voltage drops.

The gist of these errors is that the modules are having difficulty communicating with each other on the CAN bus. This can be voltage related, or it can be a failing module.

I have no idea about your scan tool. After checking the voltage, are you able to communicate with each individual module using the scan tool? Sometimes you can suss out the failing module by process of elimination.

 

Hi Y2K,

The battery and alternator are both fine. I checked them when I was having the initial issues with the car's dash screen throwing all the weird codes. That issue turned out to be a loose connection on the new battery that was installed before I bought it.

I'll throw a charger on the battery overnight and test it again in the morning.

The scanner is one that, according to several threads on here, is highly recommended. I've been reading the manual but I have no idea how to tell it to communicate with anything on the car. I've called a local shop and if I can't get this thing working by tomorrow I'm just going to hand them my credit card and see if they can get it to pass the smog test and then sell the thing to the first person that comes along with the cash. I'm too old to be dealing with this b/s. While I don't think there's anything wrong with the car, and I really like driving it, taking this long to determine what the hell the computer wants me to do is just not worth it.